CAZypedia - User contributions [en-ca]

Glycoside Hydrolase Family 16

2012-08-14T11:26:05Z

Jens Eklof:

{{CuratorApproved}}
* [[Author]]: [[User:JensEklof|Jens Eklöf]] and ^^^Jan-Hendrik Hehemann^^^
* [[Responsible Curator]]: ^^^Harry Brumer^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family 16'''
|-
|'''Clan'''
|GH-B
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH16.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolases]] of family 16 cleave β-1,4 or β-1,3 glycosidic bonds in various glucans and galactans. Some members of this family operating on xyloglucan exhibit predominant ''[[endo]]''-transglycosylase activity <cite>Baumann2007</cite>.
The substrate specificities found in GH16 are: xyloglucan:xyloglucosyltransferases (EC [{{EClink}}2.4.1.207 2.4.1.207]),
keratan-sulfate ''[[endo]]''-1,4-β-galactosidases (EC [{{EClink}}3.2.1.103 3.2.1.103]), ''[[endo]]''-1,3-β-galactanases (EC [{{EClink}}3.2.1.* 3.2.1.-]), ''[[endo]]''-1,3-β-glucanases (EC [{{EClink}}3.2.1.39 3.2.1.39]), ''[[endo]]''-1,3(4)-β-glucanases (EC [{{EClink}}3.2.1.6 3.2.1.6]), lichenases (EC [{{EClink}}3.2.1.73 3.2.1.73]), β-agarases (EC [{{EClink}}3.2.1.81 3.2.1.81]), β-porphyranases (EC [{{EClink}}3.2.1.178 3.2.1.178]) <cite>Hehemann2010</cite>, κ-carrageenases (EC [{{EClink}}3.2.1.83 3.2.1.83]) and xyloglucanases (EC [{{EClink}}3.2.1.151 3.2.1.151]).

Some invertebrate GH16 proteins have lost their catalytic amino acids and are involved in immune response activation through the Toll pathway upon binding of β-1,3 glucan. The role of the GH16 domain in this immune response is still not elucidated <cite>Lee2009</cite>.

<gallery widths=270px perrow=3 caption="Polysaccharides cleaved by GH16 enzymes">

File:AgarIII.png|'''Agar''' <br> β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''

File:Kappa_carrageenan.png|'''κ-carrageenan''' <br> β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''

File:porphyran.png|'''Porphyran''' <br>

File:laminaritetraose.png|'''β-1,3-glucan''' <br> β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''

File:keratan_sulphate.png|'''Keratan sulphate''' <br> β-D-Gal''p''-(1,4)- β-D-Glc''p''NAc 6-sulphate-(1,3)- β-D-Gal''p''-(1,4)- β-D-Glc''p''NAc 6-sulphate

File:beta_13_galactan.png|'''β-1,3-galactan''' <br> β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''

File:MLG_pentaose.png|'''β-1,4/1,3-glucan''' <br> β-D-Glc''p''-(1,4)- β-D-Glc''p''-(1,4)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,4)- β-D-Glc''p''

File:beta_14_galactan.png|'''β-1,4-galactan''' <br> β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''

File:Xyloglucan.png|'''Xyloglucan''' <br>

</gallery>
== Kinetics and Mechanism ==
Family 16 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Malet1993</cite> on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus licheniformis''.

== Catalytic Residues ==
The [[catalytic nucleophile]] was first proposed using a non-specific epoxyalkyl β-glycoside inhibitor and subsequent peptide identification by ESI-MS and Edman degradation on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus amyloliquefaciens'' <cite>Hoj1992</cite>. This was subsequently verified by azide rescue of the E134A mutant of a ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase resulting in an α-glycosyl azide from the β-glycoside substrate <cite>Viladot1998</cite>. The [[general acid/base]] residue was identified by making the E138A mutant from the ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase and subsequent azide rescue resulting in a β-glycosyl azide product <cite>Viladot1998</cite>. This mechanistic analysis on bacterial mixed-linkage [[endo]]-glucanases has been reviewed in the broader context of GH16 <cite>Planas2000</cite>.

== Three-dimensional structures ==
Proteins in family GH16 share the β-jelly-roll fold in which two β-sheets align in a sandwich like manner and its β-strands are bent around a perpendicular oriented substrate binding cleft. The first solved 3D structure was a hybrid protein of lichenase M from ''Paenibacillus macerans'' and BglA from ''Bacillus amyloliquefaciens'' ([{{PDBlink}}1byh PDB 1byh]) in 1992 <cite>Keitel1993</cite>. Several three-dimensional structures have been solved of family 16 members of archeal, bacterial, and eukaryotic origin.
The first eukaryotic 3D structure was the xyloglucan ''endo''-transglycosylase ''Ptt''XET16-34 from ''Populus tremula×tremuloides'' ([{{PDBlink}}1umz PDB 1umz]) <cite>Johansson2004</cite>. The first archeal 3D structure was a ''[[endo]]''-1,3-β-glucanase Lam16 from ''Pyrococcus furiosus'' ([{{PDBlink}}2vy0 PDB 2vy0]) <cite>Ilari2009</cite>.

== Evolution of GH16 ==
[[Image:TreeGH16new.png|thumb|right|450px|Evolution of family 16 (''click to enlarge'')]]
Family 16 is a member of [[clans|clan]] GH-B together with [[GH7]] and both families share the β-jellyroll fold. The different specificities of family 16 were proposed to have been evolved from an ancestral β-1,3-glucanase <cite>Barbeyron1998</cite>. The first branching in family 16 lead to the evolution of the κ-carrageenases and the β-agarases and a later branching event lead to the lichenases and the XETs <cite>Michel2001</cite> (see figure). This evolutionary scenario was supported by a structure based phylogeny approach. In GH16 the active site residues are located in one beta-strand at the center of the substrate binding cleft and encoded within the signature motive EXDXXE or EXDXE. These motives feature two topologies, the beta-bulge motive which is more frequent in GH16 compared to the regular beta-strand, in which one amino acid is deleted. Due to the large expansion of the beta-bulge motive and its appearance in the related GH7 Michel et al. proposed that the ancestral enzyme of both families contained the beta-bulge explaining its wide distribution in GH16. This motive subsequently evolved to become the regular beta-strand that is common in contemporary XETs and lichenases.

== Family firsts ==
; First stereochemistry determination : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase by NMR <cite>Malet1993</cite>.
; First [[catalytic nucleophile]] identification : Suggested in ''Bacillus amyloliquefaciens'' 1,3-1,4-β-D-glucan 4-glucanohydrolase via non-specific epoxyalkyl β-glycoside labeling <cite>Hoj1992</cite>. Later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First [[general acid/base]] residue identification : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase, first suggested by sequence homology and mutational studies <cite>Juncosa1994</cite>. This was later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First 3-D structure : A hybrid lichenase (''Bacillus amyloliquefaciens'' and ''Paenibacillus macerans'') by X-ray crystallography ([{{PDBlink}}1byh PDB 1byh]) <cite>Keitel1993</cite>.

== Reference list ==
<biblio>
#Johansson2004 pmid=15020748
#Hoj1992 pmid=1360982
#Malet1993 pmid=8280073
#Keitel1993 pmid=8099449
#Juncosa1994 pmid=8182059
#Viladot1998 pmid=9698381
#Ilari2009 pmid=19154353
#Michel2001 pmid=11435116 tree GH16
#Barbeyron1998 pmid=9580981 first GH16 paper
#Baumann2007 pmid=17557806
#Planas2000 pmid=11150614
#Hehemann2010 pmid=20376150
#Kotake2011 pmid=21653698
#Lee2009 pmid=19712587
</biblio>


[[Category:Glycoside Hydrolase Families|GH016]]

File:Porphyran.png

2012-02-16T01:54:19Z

Jens Eklof: uploaded a new version of "File:Porphyran.png"

File:Porphyran.png

2012-02-16T01:53:16Z

Jens Eklof: uploaded a new version of "File:Porphyran.png": Reverted to version as of 02:27, 21 January 2012

File:Porphyran.png

2012-02-16T01:52:44Z

Jens Eklof: uploaded a new version of "File:Porphyran.png"

Glycoside Hydrolase Family 16

2012-02-09T23:47:12Z

Jens Eklof:

{{CuratorApproved}}
* [[Author]]: [[User:JensEklof|Jens Eklöf]] and ^^^Jan-Hendrik Hehemann^^^
* [[Responsible Curator]]: ^^^Harry Brumer^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family 16'''
|-
|'''Clan'''
|GH-B
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH16.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolases]] of family 16 enzymes cleave β-1,4 or β-1,3 glycosidic bonds in various glucans and galactans. Some members of this family operating on xyloglucan exhibit predominant ''[[endo]]''-transglycosylase activity <cite>Baumann2007</cite>.
The substrate specificities found in GH16 are: xyloglucan:xyloglucosyltransferases (EC [{{EClink}}2.4.1.207 2.4.1.207]),
keratan-sulfate ''[[endo]]''-1,4-β-galactosidases (EC [{{EClink}}3.2.1.103 3.2.1.103]), ''[[endo]]''-1,3-β-galactanases (EC [{{EClink}}3.2.1.* 3.2.1.-]), ''[[endo]]''-1,3-β-glucanases (EC [{{EClink}}3.2.1.39 3.2.1.39]), ''[[endo]]''-1,3(4)-β-glucanases (EC [{{EClink}}3.2.1.6 3.2.1.6]), lichenases (EC [{{EClink}}3.2.1.73 3.2.1.73]), β-agarases (EC [{{EClink}}3.2.1.81 3.2.1.81]), β-porphyranases (EC [{{EClink}}3.2.1.178 3.2.1.178]) <cite>Hehemann2010</cite>, κ-carrageenases (EC [{{EClink}}3.2.1.83 3.2.1.83]) and xyloglucanases (EC [{{EClink}}3.2.1.151 3.2.1.151]).

Some invertebrate GH16 proteins have lost their catalytic amino acids and are involved in immune response activation through the Toll pathway upon binding of β-1,3 glucan. The role of the GH16 domain in this immune response is still not elucidated <cite>Lee2009</cite>.

<gallery widths=270px perrow=3 caption="Polysaccharides cleaved by GH16 enzymes">

File:AgarIII.png|'''Agar''' <br> β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''

File:Kappa_carrageenan.png|'''κ-carrageenan''' <br> β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''

File:porphyran.png|'''Porphyran''' <br>

File:laminaritetraose.png|'''β-1,3-glucan''' <br> β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''

File:keratan_sulphate.png|'''Keratan sulphate''' <br>

File:beta_13_galactan.png|'''β-1,3-galactan''' <br> β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''

File:MLG_pentaose.png|'''β-1,4/1,3-glucan''' <br> β-D-Glc''p''-(1,4)- β-D-Glc''p''-(1,4)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,4)- β-D-Glc''p''

File:beta_14_galactan.png|'''β-1,4-galactan''' <br> β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''

File:Xyloglucan.png|'''Xyloglucan''' <br>

</gallery>
== Kinetics and Mechanism ==
Family 16 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Malet1993</cite> on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus licheniformis''.

== Catalytic Residues ==
The [[catalytic nucleophile]] was first proposed using a non-specific epoxyalkyl β-glycoside inhibitor and subsequent peptide identification by ESI-MS and Edman degradation on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus amyloliquefaciens'' <cite>Hoj1992</cite>. This was subsequently verified by azide rescue of the E134A mutant of a ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase resulting in an α-glycosyl azide from the β-glycoside substrate <cite>Viladot1998</cite>. The [[general acid/base]] residue was identified by making the E138A mutant from the ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase and subsequent azide rescue resulting in a β-glycosyl azide product <cite>Viladot1998</cite>. This mechanistic analysis on bacterial mixed-linkage [[endo]]-glucanases has been reviewed in the broader context of GH16 <cite>Planas2000</cite>.

== Three-dimensional structures ==
Several three-dimensional structures have been solved of family 16 members of archeal, bacterial, and eukaryotic origin. The first solved 3D structure was a hybrid protein of lichenase M from ''Paenibacillus macerans'' and BglA from ''Bacillus amyloliquefaciens'' ([{{PDBlink}}1byh PDB 1byh]) in 1992 <cite>Keitel1993</cite>.
The first eukaryotic 3D structure was the xyloglucan ''endo''-transglycosylase ''Ptt''XET16-34 from ''Populus tremula×tremuloides'' ([{{PDBlink}}1umz PDB 1umz]) <cite>Johansson2004</cite>. The first archeal 3D structure was a ''[[endo]]''-1,3-β-glucanase Lam16 from ''Pyrococcus furiosus'' ([{{PDBlink}}2vy0 PDB 2vy0]) <cite>Ilari2009</cite>.

== Evolution of GH16 ==
[[Image:TreeGH16.png|thumb|right|450px|Evolution of family 16 (''click to enlarge'')]]
Family 16 is a member of [[clans|clan]] GH-B together with family 7 with whom they share their β-jellyroll fold. The different specificities of family 16 has been proposed to have evolved from an ancestral β-1,3-glucanase <cite>Barbeyron1998</cite>. The first branching in family 16 lead to the evolution of the κ-carrageenases and the β-agarases and a later branching event lead to the arisal of the lichenases and the XETs <cite>Michel2001</cite> (see figure).

== Family firsts ==
; First stereochemistry determination : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase by NMR <cite>Malet1993</cite>.
; First [[catalytic nucleophile]] identification : Suggested in ''Bacillus amyloliquefaciens'' 1,3-1,4-β-D-glucan 4-glucanohydrolase via non-specific epoxyalkyl β-glycoside labelling<cite>Hoj1992</cite>. Later verified in by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First [[general acid/base]] residue identification : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase, first suggested by sequence homology and mutational studies <cite>Juncosa1994</cite>. This was later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First 3-D structure : A hybrid lichenase (''Bacillus amyloliquefaciens'' and ''Paenibacillus macerans'') by X-ray crystallography ([{{PDBlink}}1byh PDB 1byh]) <cite>Keitel1993</cite>.

== Reference list ==
<biblio>
#Johansson2004 pmid=15020748
#Hoj1992 pmid=1360982
#Malet1993 pmid=8280073
#Keitel1993 pmid=8099449
#Juncosa1994 pmid=8182059
#Viladot1998 pmid=9698381
#Ilari2009 pmid=19154353
#Michel2001 pmid=11435116 tree GH16
#Barbeyron1998 pmid=9580981 first GH16 paper
#Baumann2007 pmid=17557806
#Planas2000 pmid=11150614
#Hehemann2010 pmid=20376150
#Kotake2011 pmid=21653698
#Lee2009 pmid=19712587
</biblio>


[[Category:Glycoside Hydrolase Families|GH016]]

Glycoside Hydrolase Family 16

2012-02-09T23:45:46Z

Jens Eklof:

{{CuratorApproved}}
* [[Author]]: [[User:JensEklof|Jens Eklöf]] and ^^^Jan-Hendrik Hehemann^^^
* [[Responsible Curator]]: ^^^Harry Brumer^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family 16'''
|-
|'''Clan'''
|GH-B
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH16.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolases]] of family 16 enzymes cleave β-1,4 or β-1,3 glycosidic bonds in various glucans and galactans. Some members of this family operating on xyloglucan exhibit predominant ''[[endo]]''-transglycosylase activity <cite>Baumann2007</cite>.
The substrate specificities found in GH16 are: xyloglucan:xyloglucosyltransferases (EC [{{EClink}}2.4.1.207 2.4.1.207]),
keratan-sulfate ''[[endo]]''-1,4-β-galactosidases (EC [{{EClink}}3.2.1.103 3.2.1.103]), ''[[endo]]''-1,3-β-galactanases (EC [{{EClink}}3.2.1.* 3.2.1.-]), ''[[endo]]''-1,3-β-glucanases (EC [{{EClink}}3.2.1.39 3.2.1.39]), ''[[endo]]''-1,3(4)-β-glucanases (EC [{{EClink}}3.2.1.6 3.2.1.6]), lichenases (EC [{{EClink}}3.2.1.73 3.2.1.73]), β-agarases (EC [{{EClink}}3.2.1.81 3.2.1.81]), β-porphyranases (EC [{{EClink}}3.2.1.178 3.2.1.178]) <cite>Hehemann2010</cite>, κ-carrageenases (EC [{{EClink}}3.2.1.83 3.2.1.83]) and xyloglucanases (EC [{{EClink}}3.2.1.151 3.2.1.151]).

Some invertebrate GH16 proteins have lost their catalytic amino acids and are involved in immune response activation through the Toll pathway upon binding of β-1,3 glucan. The role of the GH16 domain in this immune response is still not elucidated <cite>Lee2009</cite>.

<gallery widths=270px perrow=3 caption="Polysaccharides cleaved by GH16 enzymes">

File:AgarIII.png|'''Agar''' <br> β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''

File:Kappa_carrageenan.png|'''κ-carrageenan''' <br> β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''

File:porphyran.png|'''Porphyran''' <br>

File:laminaritetraose.png|'''β-1,3-glucan''' <br> β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''

File:keratan_sulphate.png|'''Keratan sulphate''' <br>

File:beta_13_galactan.png|'''β-1,3-galactan''' <br> β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''

File:MLG_pentaose.png|'''β-1,4/1,3-glucan''' <br>

File:beta_14_galactan.png|'''β-1,4-galactan''' <br> β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''

File:Xyloglucan.png|'''Xyloglucan''' <br>

</gallery>
== Kinetics and Mechanism ==
Family 16 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Malet1993</cite> on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus licheniformis''.

== Catalytic Residues ==
The [[catalytic nucleophile]] was first proposed using a non-specific epoxyalkyl β-glycoside inhibitor and subsequent peptide identification by ESI-MS and Edman degradation on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus amyloliquefaciens'' <cite>Hoj1992</cite>. This was subsequently verified by azide rescue of the E134A mutant of a ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase resulting in an α-glycosyl azide from the β-glycoside substrate <cite>Viladot1998</cite>. The [[general acid/base]] residue was identified by making the E138A mutant from the ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase and subsequent azide rescue resulting in a β-glycosyl azide product <cite>Viladot1998</cite>. This mechanistic analysis on bacterial mixed-linkage [[endo]]-glucanases has been reviewed in the broader context of GH16 <cite>Planas2000</cite>.

== Three-dimensional structures ==
Several three-dimensional structures have been solved of family 16 members of archeal, bacterial, and eukaryotic origin. The first solved 3D structure was a hybrid protein of lichenase M from ''Paenibacillus macerans'' and BglA from ''Bacillus amyloliquefaciens'' ([{{PDBlink}}1byh PDB 1byh]) in 1992 <cite>Keitel1993</cite>.
The first eukaryotic 3D structure was the xyloglucan ''endo''-transglycosylase ''Ptt''XET16-34 from ''Populus tremula×tremuloides'' ([{{PDBlink}}1umz PDB 1umz]) <cite>Johansson2004</cite>. The first archeal 3D structure was a ''[[endo]]''-1,3-β-glucanase Lam16 from ''Pyrococcus furiosus'' ([{{PDBlink}}2vy0 PDB 2vy0]) <cite>Ilari2009</cite>.

== Evolution of GH16 ==
[[Image:TreeGH16.png|thumb|right|450px|Evolution of family 16 (''click to enlarge'')]]
Family 16 is a member of [[clans|clan]] GH-B together with family 7 with whom they share their β-jellyroll fold. The different specificities of family 16 has been proposed to have evolved from an ancestral β-1,3-glucanase <cite>Barbeyron1998</cite>. The first branching in family 16 lead to the evolution of the κ-carrageenases and the β-agarases and a later branching event lead to the arisal of the lichenases and the XETs <cite>Michel2001</cite> (see figure).

== Family firsts ==
; First stereochemistry determination : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase by NMR <cite>Malet1993</cite>.
; First [[catalytic nucleophile]] identification : Suggested in ''Bacillus amyloliquefaciens'' 1,3-1,4-β-D-glucan 4-glucanohydrolase via non-specific epoxyalkyl β-glycoside labelling<cite>Hoj1992</cite>. Later verified in by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First [[general acid/base]] residue identification : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase, first suggested by sequence homology and mutational studies <cite>Juncosa1994</cite>. This was later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First 3-D structure : A hybrid lichenase (''Bacillus amyloliquefaciens'' and ''Paenibacillus macerans'') by X-ray crystallography ([{{PDBlink}}1byh PDB 1byh]) <cite>Keitel1993</cite>.

== Reference list ==
<biblio>
#Johansson2004 pmid=15020748
#Hoj1992 pmid=1360982
#Malet1993 pmid=8280073
#Keitel1993 pmid=8099449
#Juncosa1994 pmid=8182059
#Viladot1998 pmid=9698381
#Ilari2009 pmid=19154353
#Michel2001 pmid=11435116 tree GH16
#Barbeyron1998 pmid=9580981 first GH16 paper
#Baumann2007 pmid=17557806
#Planas2000 pmid=11150614
#Hehemann2010 pmid=20376150
#Kotake2011 pmid=21653698
#Lee2009 pmid=19712587
</biblio>


[[Category:Glycoside Hydrolase Families|GH016]]

Glycoside Hydrolase Family 16

2012-02-09T23:44:46Z

Jens Eklof:

{{CuratorApproved}}
* [[Author]]: [[User:JensEklof|Jens Eklöf]] and ^^^Jan-Hendrik Hehemann^^^
* [[Responsible Curator]]: ^^^Harry Brumer^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family 16'''
|-
|'''Clan'''
|GH-B
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH16.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolases]] of family 16 enzymes cleave β-1,4 or β-1,3 glycosidic bonds in various glucans and galactans. Some members of this family operating on xyloglucan exhibit predominant ''[[endo]]''-transglycosylase activity <cite>Baumann2007</cite>.
The substrate specificities found in GH16 are: xyloglucan:xyloglucosyltransferases (EC [{{EClink}}2.4.1.207 2.4.1.207]),
keratan-sulfate ''[[endo]]''-1,4-β-galactosidases (EC [{{EClink}}3.2.1.103 3.2.1.103]), ''[[endo]]''-1,3-β-galactanases (EC [{{EClink}}3.2.1.* 3.2.1.-]), ''[[endo]]''-1,3-β-glucanases (EC [{{EClink}}3.2.1.39 3.2.1.39]), ''[[endo]]''-1,3(4)-β-glucanases (EC [{{EClink}}3.2.1.6 3.2.1.6]), lichenases (EC [{{EClink}}3.2.1.73 3.2.1.73]), β-agarases (EC [{{EClink}}3.2.1.81 3.2.1.81]), β-porphyranases (EC [{{EClink}}3.2.1.178 3.2.1.178]) <cite>Hehemann2010</cite>, κ-carrageenases (EC [{{EClink}}3.2.1.83 3.2.1.83]) and xyloglucanases (EC [{{EClink}}3.2.1.151 3.2.1.151]).

Some invertebrate GH16 proteins have lost their catalytic amino acids and are involved in immune response activation through the Toll pathway upon binding of β-1,3 glucan. The role of the GH16 domain in this immune response is still not elucidated <cite>Lee2009</cite>.

<gallery widths=270px perrow=3 caption="Polysaccharides cleaved by GH16 enzymes">

File:AgarIII.png|'''Agar''' <br> β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''

File:Kappa_carrageenan.png|'''κ-carrageenan''', β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-D-3,6-anhydro-Gal''p''

File:porphyran.png|'''Porphyran'''

File:laminaritetraose.png|'''β-1,3-glucan''', β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''

File:keratan_sulphate.png|'''Keratan sulphate'''

File:beta_13_galactan.png|'''β-1,3-galactan''', β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''

File:MLG_pentaose.png|'''β-1,4/1,3-glucan'''

File:beta_14_galactan.png|'''β-1,4-galactan''', β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''

File:Xyloglucan.png|'''Xyloglucan'''

</gallery>
== Kinetics and Mechanism ==
Family 16 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Malet1993</cite> on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus licheniformis''.

== Catalytic Residues ==
The [[catalytic nucleophile]] was first proposed using a non-specific epoxyalkyl β-glycoside inhibitor and subsequent peptide identification by ESI-MS and Edman degradation on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus amyloliquefaciens'' <cite>Hoj1992</cite>. This was subsequently verified by azide rescue of the E134A mutant of a ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase resulting in an α-glycosyl azide from the β-glycoside substrate <cite>Viladot1998</cite>. The [[general acid/base]] residue was identified by making the E138A mutant from the ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase and subsequent azide rescue resulting in a β-glycosyl azide product <cite>Viladot1998</cite>. This mechanistic analysis on bacterial mixed-linkage [[endo]]-glucanases has been reviewed in the broader context of GH16 <cite>Planas2000</cite>.

== Three-dimensional structures ==
Several three-dimensional structures have been solved of family 16 members of archeal, bacterial, and eukaryotic origin. The first solved 3D structure was a hybrid protein of lichenase M from ''Paenibacillus macerans'' and BglA from ''Bacillus amyloliquefaciens'' ([{{PDBlink}}1byh PDB 1byh]) in 1992 <cite>Keitel1993</cite>.
The first eukaryotic 3D structure was the xyloglucan ''endo''-transglycosylase ''Ptt''XET16-34 from ''Populus tremula×tremuloides'' ([{{PDBlink}}1umz PDB 1umz]) <cite>Johansson2004</cite>. The first archeal 3D structure was a ''[[endo]]''-1,3-β-glucanase Lam16 from ''Pyrococcus furiosus'' ([{{PDBlink}}2vy0 PDB 2vy0]) <cite>Ilari2009</cite>.

== Evolution of GH16 ==
[[Image:TreeGH16.png|thumb|right|450px|Evolution of family 16 (''click to enlarge'')]]
Family 16 is a member of [[clans|clan]] GH-B together with family 7 with whom they share their β-jellyroll fold. The different specificities of family 16 has been proposed to have evolved from an ancestral β-1,3-glucanase <cite>Barbeyron1998</cite>. The first branching in family 16 lead to the evolution of the κ-carrageenases and the β-agarases and a later branching event lead to the arisal of the lichenases and the XETs <cite>Michel2001</cite> (see figure).

== Family firsts ==
; First stereochemistry determination : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase by NMR <cite>Malet1993</cite>.
; First [[catalytic nucleophile]] identification : Suggested in ''Bacillus amyloliquefaciens'' 1,3-1,4-β-D-glucan 4-glucanohydrolase via non-specific epoxyalkyl β-glycoside labelling<cite>Hoj1992</cite>. Later verified in by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First [[general acid/base]] residue identification : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase, first suggested by sequence homology and mutational studies <cite>Juncosa1994</cite>. This was later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First 3-D structure : A hybrid lichenase (''Bacillus amyloliquefaciens'' and ''Paenibacillus macerans'') by X-ray crystallography ([{{PDBlink}}1byh PDB 1byh]) <cite>Keitel1993</cite>.

== Reference list ==
<biblio>
#Johansson2004 pmid=15020748
#Hoj1992 pmid=1360982
#Malet1993 pmid=8280073
#Keitel1993 pmid=8099449
#Juncosa1994 pmid=8182059
#Viladot1998 pmid=9698381
#Ilari2009 pmid=19154353
#Michel2001 pmid=11435116 tree GH16
#Barbeyron1998 pmid=9580981 first GH16 paper
#Baumann2007 pmid=17557806
#Planas2000 pmid=11150614
#Hehemann2010 pmid=20376150
#Kotake2011 pmid=21653698
#Lee2009 pmid=19712587
</biblio>


[[Category:Glycoside Hydrolase Families|GH016]]

Glycoside Hydrolase Family 16

2012-02-09T23:35:06Z

Jens Eklof:

{{CuratorApproved}}
* [[Author]]: [[User:JensEklof|Jens Eklöf]] and ^^^Jan-Hendrik Hehemann^^^
* [[Responsible Curator]]: ^^^Harry Brumer^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family 16'''
|-
|'''Clan'''
|GH-B
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH16.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolases]] of family 16 enzymes cleave β-1,4 or β-1,3 glycosidic bonds in various glucans and galactans. Some members of this family operating on xyloglucan exhibit predominant ''[[endo]]''-transglycosylase activity <cite>Baumann2007</cite>.
The substrate specificities found in GH16 are: xyloglucan:xyloglucosyltransferases (EC [{{EClink}}2.4.1.207 2.4.1.207]),
keratan-sulfate ''[[endo]]''-1,4-β-galactosidases (EC [{{EClink}}3.2.1.103 3.2.1.103]), ''[[endo]]''-1,3-β-galactanases (EC [{{EClink}}3.2.1.* 3.2.1.-]), ''[[endo]]''-1,3-β-glucanases (EC [{{EClink}}3.2.1.39 3.2.1.39]), ''[[endo]]''-1,3(4)-β-glucanases (EC [{{EClink}}3.2.1.6 3.2.1.6]), lichenases (EC [{{EClink}}3.2.1.73 3.2.1.73]), β-agarases (EC [{{EClink}}3.2.1.81 3.2.1.81]), β-porphyranases (EC [{{EClink}}3.2.1.178 3.2.1.178]) <cite>Hehemann2010</cite>, κ-carrageenases (EC [{{EClink}}3.2.1.83 3.2.1.83]) and xyloglucanases (EC [{{EClink}}3.2.1.151 3.2.1.151]).

Some invertebrate GH16 proteins have lost their catalytic amino acids and are involved in immune response activation through the Toll pathway upon binding of β-1,3 glucan. The role of the GH16 domain in this immune response is still not elucidated <cite>Lee2009</cite>.

<gallery widths=270px perrow=3 caption="Polysaccharides cleaved by GH16 enzymes">

File:AgarIII.png|'''Agar''' <br> β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Galp

File:Kappa_carrageenan.png|'''κ-carrageenan'''

File:porphyran.png|'''Porphyran'''

File:laminaritetraose.png|'''β-1,3-glucan''', β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''

File:keratan_sulphate.png|'''Keratan sulphate'''

File:beta_13_galactan.png|'''β-1,3-galactan''', β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''

File:MLG_pentaose.png|'''β-1,4/1,3-glucan'''

File:beta_14_galactan.png|'''β-1,4-galactan''', β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''

File:Xyloglucan.png|'''Xyloglucan'''

</gallery>
== Kinetics and Mechanism ==
Family 16 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Malet1993</cite> on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus licheniformis''.

== Catalytic Residues ==
The [[catalytic nucleophile]] was first proposed using a non-specific epoxyalkyl β-glycoside inhibitor and subsequent peptide identification by ESI-MS and Edman degradation on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus amyloliquefaciens'' <cite>Hoj1992</cite>. This was subsequently verified by azide rescue of the E134A mutant of a ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase resulting in an α-glycosyl azide from the β-glycoside substrate <cite>Viladot1998</cite>. The [[general acid/base]] residue was identified by making the E138A mutant from the ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase and subsequent azide rescue resulting in a β-glycosyl azide product <cite>Viladot1998</cite>. This mechanistic analysis on bacterial mixed-linkage [[endo]]-glucanases has been reviewed in the broader context of GH16 <cite>Planas2000</cite>.

== Three-dimensional structures ==
Several three-dimensional structures have been solved of family 16 members of archeal, bacterial, and eukaryotic origin. The first solved 3D structure was a hybrid protein of lichenase M from ''Paenibacillus macerans'' and BglA from ''Bacillus amyloliquefaciens'' ([{{PDBlink}}1byh PDB 1byh]) in 1992 <cite>Keitel1993</cite>.
The first eukaryotic 3D structure was the xyloglucan ''endo''-transglycosylase ''Ptt''XET16-34 from ''Populus tremula×tremuloides'' ([{{PDBlink}}1umz PDB 1umz]) <cite>Johansson2004</cite>. The first archeal 3D structure was a ''[[endo]]''-1,3-β-glucanase Lam16 from ''Pyrococcus furiosus'' ([{{PDBlink}}2vy0 PDB 2vy0]) <cite>Ilari2009</cite>.

== Evolution of GH16 ==
[[Image:TreeGH16.png|thumb|right|450px|Evolution of family 16 (''click to enlarge'')]]
Family 16 is a member of [[clans|clan]] GH-B together with family 7 with whom they share their β-jellyroll fold. The different specificities of family 16 has been proposed to have evolved from an ancestral β-1,3-glucanase <cite>Barbeyron1998</cite>. The first branching in family 16 lead to the evolution of the κ-carrageenases and the β-agarases and a later branching event lead to the arisal of the lichenases and the XETs <cite>Michel2001</cite> (see figure).

== Family firsts ==
; First stereochemistry determination : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase by NMR <cite>Malet1993</cite>.
; First [[catalytic nucleophile]] identification : Suggested in ''Bacillus amyloliquefaciens'' 1,3-1,4-β-D-glucan 4-glucanohydrolase via non-specific epoxyalkyl β-glycoside labelling<cite>Hoj1992</cite>. Later verified in by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First [[general acid/base]] residue identification : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase, first suggested by sequence homology and mutational studies <cite>Juncosa1994</cite>. This was later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First 3-D structure : A hybrid lichenase (''Bacillus amyloliquefaciens'' and ''Paenibacillus macerans'') by X-ray crystallography ([{{PDBlink}}1byh PDB 1byh]) <cite>Keitel1993</cite>.

== Reference list ==
<biblio>
#Johansson2004 pmid=15020748
#Hoj1992 pmid=1360982
#Malet1993 pmid=8280073
#Keitel1993 pmid=8099449
#Juncosa1994 pmid=8182059
#Viladot1998 pmid=9698381
#Ilari2009 pmid=19154353
#Michel2001 pmid=11435116 tree GH16
#Barbeyron1998 pmid=9580981 first GH16 paper
#Baumann2007 pmid=17557806
#Planas2000 pmid=11150614
#Hehemann2010 pmid=20376150
#Kotake2011 pmid=21653698
#Lee2009 pmid=19712587
</biblio>


[[Category:Glycoside Hydrolase Families|GH016]]

File:Xyloglucan.png

2012-02-09T23:34:32Z

Jens Eklof:

File:AgarIII.png

2012-02-09T23:03:59Z

Jens Eklof:

File:Agar.png

2012-02-09T23:03:44Z

Jens Eklof: uploaded a new version of "File:Agar.png"

Glycoside Hydrolase Family 16

2012-02-09T23:03:15Z

Jens Eklof:

{{CuratorApproved}}
* [[Author]]: [[User:JensEklof|Jens Eklöf]] and ^^^Jan-Hendrik Hehemann^^^
* [[Responsible Curator]]: ^^^Harry Brumer^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family 16'''
|-
|'''Clan'''
|GH-B
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH16.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolases]] of family 16 enzymes cleave β-1,4 or β-1,3 glycosidic bonds in various glucans and galactans. Some members of this family operating on xyloglucan exhibit predominant ''[[endo]]''-transglycosylase activity <cite>Baumann2007</cite>.
The substrate specificities found in GH16 are: xyloglucan:xyloglucosyltransferases (EC [{{EClink}}2.4.1.207 2.4.1.207]),
keratan-sulfate ''[[endo]]''-1,4-β-galactosidases (EC [{{EClink}}3.2.1.103 3.2.1.103]), ''[[endo]]''-1,3-β-galactanases (EC [{{EClink}}3.2.1.* 3.2.1.-]), ''[[endo]]''-1,3-β-glucanases (EC [{{EClink}}3.2.1.39 3.2.1.39]), ''[[endo]]''-1,3(4)-β-glucanases (EC [{{EClink}}3.2.1.6 3.2.1.6]), lichenases (EC [{{EClink}}3.2.1.73 3.2.1.73]), β-agarases (EC [{{EClink}}3.2.1.81 3.2.1.81]), β-porphyranases (EC [{{EClink}}3.2.1.178 3.2.1.178]) <cite>Hehemann2010</cite>, κ-carrageenases (EC [{{EClink}}3.2.1.83 3.2.1.83]) and xyloglucanases (EC [{{EClink}}3.2.1.151 3.2.1.151]).

Some invertebrate GH16 proteins have lost their catalytic amino acids and are involved in immune response activation through the Toll pathway upon binding of β-1,3 glucan. The role of the GH16 domain in this immune response is still not elucidated <cite>Lee2009</cite>.

<gallery widths=270px perrow=3 caption="Polysaccharides cleaved by GH16 enzymes">

File:AgarIII.png|'''Agar''' <br> β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Gal''p''-1,3-β-D-Gal''p''-(1,4)-α-L-3,6-anhydro-Galp

File:Kappa_carrageenan.png|'''κ-carrageenan'''

File:porphyran.png|'''Porphyran'''

File:laminaritetraose.png|'''β-1,3-glucan''', β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''-(1,3)- β-D-Glc''p''

File:keratan_sulphate.png|'''Keratan sulphate'''

File:beta_13_galactan.png|'''β-1,3-galactan''', β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''-(1,3)- β-D-Gal''p''

File:MLG_pentaose.png|'''β-1,4/1,3-glucan'''

File:beta_14_galactan.png|'''β-1,4-galactan''', β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''-(1,4)- β-D-Gal''p''

File:XLFG.png|'''Xyloglucan'''

</gallery>
== Kinetics and Mechanism ==
Family 16 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Malet1993</cite> on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus licheniformis''.

== Catalytic Residues ==
The [[catalytic nucleophile]] was first proposed using a non-specific epoxyalkyl β-glycoside inhibitor and subsequent peptide identification by ESI-MS and Edman degradation on an ''[[endo]]''-1,3-1,4-β-D-glucan 4-glucanohydrolase from ''Bacillus amyloliquefaciens'' <cite>Hoj1992</cite>. This was subsequently verified by azide rescue of the E134A mutant of a ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase resulting in an α-glycosyl azide from the β-glycoside substrate <cite>Viladot1998</cite>. The [[general acid/base]] residue was identified by making the E138A mutant from the ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase and subsequent azide rescue resulting in a β-glycosyl azide product <cite>Viladot1998</cite>. This mechanistic analysis on bacterial mixed-linkage [[endo]]-glucanases has been reviewed in the broader context of GH16 <cite>Planas2000</cite>.

== Three-dimensional structures ==
Several three-dimensional structures have been solved of family 16 members of archeal, bacterial, and eukaryotic origin. The first solved 3D structure was a hybrid protein of lichenase M from ''Paenibacillus macerans'' and BglA from ''Bacillus amyloliquefaciens'' ([{{PDBlink}}1byh PDB 1byh]) in 1992 <cite>Keitel1993</cite>.
The first eukaryotic 3D structure was the xyloglucan ''endo''-transglycosylase ''Ptt''XET16-34 from ''Populus tremula×tremuloides'' ([{{PDBlink}}1umz PDB 1umz]) <cite>Johansson2004</cite>. The first archeal 3D structure was a ''[[endo]]''-1,3-β-glucanase Lam16 from ''Pyrococcus furiosus'' ([{{PDBlink}}2vy0 PDB 2vy0]) <cite>Ilari2009</cite>.

== Evolution of GH16 ==
[[Image:TreeGH16.png|thumb|right|450px|Evolution of family 16 (''click to enlarge'')]]
Family 16 is a member of [[clans|clan]] GH-B together with family 7 with whom they share their β-jellyroll fold. The different specificities of family 16 has been proposed to have evolved from an ancestral β-1,3-glucanase <cite>Barbeyron1998</cite>. The first branching in family 16 lead to the evolution of the κ-carrageenases and the β-agarases and a later branching event lead to the arisal of the lichenases and the XETs <cite>Michel2001</cite> (see figure).

== Family firsts ==
; First stereochemistry determination : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase by NMR <cite>Malet1993</cite>.
; First [[catalytic nucleophile]] identification : Suggested in ''Bacillus amyloliquefaciens'' 1,3-1,4-β-D-glucan 4-glucanohydrolase via non-specific epoxyalkyl β-glycoside labelling<cite>Hoj1992</cite>. Later verified in by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First [[general acid/base]] residue identification : ''Bacillus licheniformis'' 1,3-1,4-β-D-glucan 4-glucanohydrolase, first suggested by sequence homology and mutational studies <cite>Juncosa1994</cite>. This was later verified by azide rescue of inactivated mutants <cite>Viladot1998</cite>.
; First 3-D structure : A hybrid lichenase (''Bacillus amyloliquefaciens'' and ''Paenibacillus macerans'') by X-ray crystallography ([{{PDBlink}}1byh PDB 1byh]) <cite>Keitel1993</cite>.

== Reference list ==
<biblio>
#Johansson2004 pmid=15020748
#Hoj1992 pmid=1360982
#Malet1993 pmid=8280073
#Keitel1993 pmid=8099449
#Juncosa1994 pmid=8182059
#Viladot1998 pmid=9698381
#Ilari2009 pmid=19154353
#Michel2001 pmid=11435116 tree GH16
#Barbeyron1998 pmid=9580981 first GH16 paper
#Baumann2007 pmid=17557806
#Planas2000 pmid=11150614
#Hehemann2010 pmid=20376150
#Kotake2011 pmid=21653698
#Lee2009 pmid=19712587
</biblio>


[[Category:Glycoside Hydrolase Families|GH016]]

Glycoside Hydrolase Family 16

2012-01-20T22:15:33Z

Jens Eklof:

Glycoside Hydrolase Family 16

2012-01-20T22:14:41Z

Jens Eklof:

Glycoside Hydrolase Family 16

2012-01-20T22:13:43Z

Jens Eklof: