CAZypedia - User contributions [en-ca]

Glycoside Hydrolase Family 32

2010-02-22T11:35:31Z

Wim Van den Ende: /* Catalytic Residues */

{{CuratorApproved}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>. However, endo-inulinases use a glutamate as catalytic nucleophile.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>5</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>6</cite> and fructan 1-exohydrolase <cite>7</cite> ), as well as one fungal exo-inulinase <cite>8</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>9</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<biblio>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

Glycoside Hydrolase Family 32

2010-02-22T11:34:09Z

Wim Van den Ende: Undo revision 4070 by Wim Van den Ende (Talk)

{{CuratorApproved}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two invariant residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified experimentally in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>5</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>6</cite> and fructan 1-exohydrolase <cite>7</cite> ), as well as one fungal exo-inulinase <cite>8</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>9</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<biblio>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

Glycoside Hydrolase Family 32

2010-02-22T11:33:02Z

Wim Van den Ende: Undo revision 4069 by Wim Van den Ende (Talk)

{{CuratorApproved}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two invariant residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified experimentally in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>6</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>7</cite> and fructan 1-exohydrolase <cite>8</cite> ), as well as one fungal exo-inulinase <cite>9</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>10</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<biblio>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

Glycoside Hydrolase Family 32

2010-02-22T11:18:39Z

Wim Van den Ende: /* Catalytic Residues */

{{CuratorApproved}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>. However, endo-inulinases contain a glutamate as nucleophile <cite>5<cite>.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>6</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>7</cite> and fructan 1-exohydrolase <cite>8</cite> ), as well as one fungal exo-inulinase <cite>9</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>10</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<biblio>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

Glycoside Hydrolase Family 32

2010-02-22T11:15:55Z

Wim Van den Ende: /* Catalytic Residues */

{{CuratorApproved}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>. However, endo-inulinases contain a glutamate as nucleophile <cite>5<cite>.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>5</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>6</cite> and fructan 1-exohydrolase <cite>7</cite> ), as well as one fungal exo-inulinase <cite>8</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>9</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<biblio>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

Glycoside Hydrolase Family 68

2010-02-19T16:46:27Z

Wim Van den Ende: /* Catalytic Residues */

{{CuratorApproved}}
* [[Author]]: ^^^Tirso Pons^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Wim Van den Ende^^^
----


<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH68'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH68.html
|}
</div>


== Substrate specificities ==
Glycoside hydrolase family GH68 enzymes include levansucrase (sucrose:2,6-β-D-fructan 6-β-D-fructosyltransferase; EC [{{EClink}}2.4.1.10 2.4.1.10]), β-fructofuranosidase (EC [{{EClink}}3.2.1.26 3.2.1.26]), and inulosucrase (EC [{{EClink}}2.4.1.9 2.4.1.9]). All these enzymes use sucrose as their preferential donor substrate. Many of them can create very long levan-type fructans (catalyzed by levansucrases) or inulin-type of fructans (catalyzed by inulosucrases), as well as fructooligosacharides (FOS). However, some GH68 enzymes can also use fructan as donor substrate (in the abscence of sucrose or at a high fructan/sucrose ratio).

== Kinetics and Mechanism ==
Family GH68 enzymes as well as those included in [[GH32]] are retaining enzymes <cite>1</cite>. The levansucrases from ''Bacillus subtilis'', ''Gluconacetobacter diazotrophicus'', and ''Streptococcus salivarius'' catalyze transfructosylation via a ping-pong mechanism involving the formation of a transient fructosyl-enzyme intermediate <cite>2 3 4 5</cite>. At low sucrose concentrations levansucrase functions as a hydrolase with water as acceptor, whereas at higher substrate concentrations it adds fructosyl units to a variety of acceptors including glucose, fructan and sucrose <cite>2</cite>. Bacterial levansucrases, whatever their origin, catalyze all these reactions but with different efficiency.

== Catalytic Residues ==
Retaining glycosidases catalyze hydrolysis in two steps involving a covalent glycosyl enzyme intermediate. The two invariant residues, responsible for the catalytic reaction in family GH68 enzymes, have first been identified experimentally in bacterial levansucrases as an aspartate located close to the N-terminus acting as the catalytic nucleophile (http://www.cazypedia.org/index.php/Catalytic_nucleophile) and a glutamate acting as the general acid/base (http://www.cazypedia.org/index.php/General_acid/base)<cite>6 7</cite>. In addition, a conserved aspartate residue in the "Arg-Asp-Pro (RDP) motif" stabilizes the transition state <cite>5 7 8</cite>. The three equivalent acidic residues have been mutated in a β-fructofuranosidase from ''Arthrobacter globiformis'' IFO 3062 <cite>9</cite>, and in a levansucrase and a inulosucrase from ''Lactobacillus reuteri'' 121 <cite>10</cite>.

== Three-dimensional structures ==
Currently, only two different three dimensional structures of family GH68 enzymes have been solved. The first crystal structure was reported for the bacterial levansucrase (SacB) from ''Bacillus subtilis'' subsp. subtilis str. 168 <cite>6</cite>. The second one corresponds to levansucrase (LdsA) from ''Gluconacetobacter diazotrophicus'' SRT4 <cite>11</cite>. These structures display a 5-fold β-propeller topology, and therefore GH families 68 and [[GH32|32]] have been combined in clan GH-J. On the other hand, a structural relationship of the catalytic core exists to family GH68 and family [[GH43]], as predicted by detailed sequence analysis<cite>12</cite>.

== Family Firsts ==
;First stereochemistry determination: ''Bacillus subtilis'' levansucrase <cite>2</cite>.
;First catalytic nucleophile identification: ''Bacillus subtilis'' levansucrase <cite>6</cite>.
;First general acid/base residue identification: ''Zymomonas mobilis'' levansucrase <cite>7</cite>.
;First stabilizing transition-state residue identification: ''Gluconacetobacter diazotrophicus'' levansucrase <cite>8</cite>.
;First prediction of a common beta-propeller catalytic domain in GH68 / clan GH-J: ''Gluconacetobacter diazotrophicus'' levansucrase <cite>13 14</cite>.
;First 3-D structure: ''Bacillus subtilis'' levansucrase <cite>6</cite>.

== References ==
<biblio>
#1 pmid=13174523
#2 pmid=4206083
#3 pmid=814002
#4 pmid=7619044
#5 pmid=10393084
#6 pmid=14517548
#7 pmid=12359071
#8 pmid=9895294
#9 pmid=16233623
#10 pmid=14988011
#11 pmid=15869470
#12 pmid=11093261
#13 pmid=9829697
#14 pmid=11305239
</biblio>

[[Category:Glycoside Hydrolase Families|GH068]]

Glycoside Hydrolase Family 68

2010-02-19T16:43:16Z

Wim Van den Ende:

{{CuratorApproved}}
* [[Author]]: ^^^Tirso Pons^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Wim Van den Ende^^^
----


<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH68'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH68.html
|}
</div>


== Substrate specificities ==
Glycoside hydrolase family GH68 enzymes include levansucrase (sucrose:2,6-β-D-fructan 6-β-D-fructosyltransferase; EC [{{EClink}}2.4.1.10 2.4.1.10]), β-fructofuranosidase (EC [{{EClink}}3.2.1.26 3.2.1.26]), and inulosucrase (EC [{{EClink}}2.4.1.9 2.4.1.9]). All these enzymes use sucrose as their preferential donor substrate. Many of them can create very long levan-type fructans (catalyzed by levansucrases) or inulin-type of fructans (catalyzed by inulosucrases), as well as fructooligosacharides (FOS). However, some GH68 enzymes can also use fructan as donor substrate (in the abscence of sucrose or at a high fructan/sucrose ratio).

== Kinetics and Mechanism ==
Family GH68 enzymes as well as those included in [[GH32]] are retaining enzymes <cite>1</cite>. The levansucrases from ''Bacillus subtilis'', ''Gluconacetobacter diazotrophicus'', and ''Streptococcus salivarius'' catalyze transfructosylation via a ping-pong mechanism involving the formation of a transient fructosyl-enzyme intermediate <cite>2 3 4 5</cite>. At low sucrose concentrations levansucrase functions as a hydrolase with water as acceptor, whereas at higher substrate concentrations it adds fructosyl units to a variety of acceptors including glucose, fructan and sucrose <cite>2</cite>. Bacterial levansucrases, whatever their origin, catalyze all these reactions but with different efficiency.

== Catalytic Residues ==
Retaining glycosidases catalyze hydrolysis in two steps involving a covalent glycosyl enzyme intermediate. The two invariant residues, responsible for the catalytic reaction in family GH68 enzymes, have first been identified experimentally in bacterial levansucrases as an aspartate located close to the N-terminus acting as the catalytic nucleophile (http://www.cazypedia.org/index.php/Catalytic_nucleophile)and a glutamate acting as the general acid/base (http://www.cazypedia.org/index.php/General_acid/base)<cite>6 7</cite>. In addition, a conserved aspartate residue in the "Arg-Asp-Pro (RDP) motif" stabilizes the transition state <cite>5 7 8</cite>. The three equivalent acidic residues have been mutated in a β-fructofuranosidase from ''Arthrobacter globiformis'' IFO 3062 <cite>9</cite>, and in a levansucrase and a inulosucrase from ''Lactobacillus reuteri'' 121 <cite>10</cite>.

== Three-dimensional structures ==
Currently, only two different three dimensional structures of family GH68 enzymes have been solved. The first crystal structure was reported for the bacterial levansucrase (SacB) from ''Bacillus subtilis'' subsp. subtilis str. 168 <cite>6</cite>. The second one corresponds to levansucrase (LdsA) from ''Gluconacetobacter diazotrophicus'' SRT4 <cite>11</cite>. These structures display a 5-fold β-propeller topology, and therefore GH families 68 and [[GH32|32]] have been combined in clan GH-J. On the other hand, a structural relationship of the catalytic core exists to family GH68 and family [[GH43]], as predicted by detailed sequence analysis<cite>12</cite>.

== Family Firsts ==
;First stereochemistry determination: ''Bacillus subtilis'' levansucrase <cite>2</cite>.
;First catalytic nucleophile identification: ''Bacillus subtilis'' levansucrase <cite>6</cite>.
;First general acid/base residue identification: ''Zymomonas mobilis'' levansucrase <cite>7</cite>.
;First stabilizing transition-state residue identification: ''Gluconacetobacter diazotrophicus'' levansucrase <cite>8</cite>.
;First prediction of a common beta-propeller catalytic domain in GH68 / clan GH-J: ''Gluconacetobacter diazotrophicus'' levansucrase <cite>13 14</cite>.
;First 3-D structure: ''Bacillus subtilis'' levansucrase <cite>6</cite>.

== References ==
<biblio>
#1 pmid=13174523
#2 pmid=4206083
#3 pmid=814002
#4 pmid=7619044
#5 pmid=10393084
#6 pmid=14517548
#7 pmid=12359071
#8 pmid=9895294
#9 pmid=16233623
#10 pmid=14988011
#11 pmid=15869470
#12 pmid=11093261
#13 pmid=9829697
#14 pmid=11305239
</biblio>

[[Category:Glycoside Hydrolase Families|GH068]]

Glycoside Hydrolase Family 32

2010-01-08T06:09:12Z

Wim Van den Ende:

{{UnderConstruction}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two invariant residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified experimentally in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>5</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>6</cite> and fructan 1-exohydrolase <cite>7</cite> ), as well as one fungal exo-inulinase <cite>8</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>9</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<[[biblio]]>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

Glycoside Hydrolase Family 32

2010-01-08T06:01:28Z

Wim Van den Ende:

{{UnderConstruction}}
* [[Author]]s: ^^^Mirjam Czjzek^^^ and ^^^Wim Van den Ende^^^
* [[Responsible Curator]]: ^^^Mirjam Czjzek^^^
----

<div style="float:right">
{| {{Prettytable}}
|-
|{{Hl2}} colspan="2" align="center" |'''Glycoside Hydrolase Family GH32'''
|-
|'''Clan'''
|GH-J
|-
|'''Mechanism'''
|retaining
|-
|'''Active site residues'''
|known
|-
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
|-
| colspan="2" |http://www.cazy.org/fam/GH32.html
|}
</div>

== Substrate specificities ==
[[Glycoside hydrolase]] family GH32 contains one of the earliest described enzyme activities, namely that of 'inverting' sucrose, from which is derived the name of 'invertase' (EC 3.2.1.26), discovered in the second half of the 19th century <cite>1</cite>. Besides the 'historical' invertases, this family also contains enzymes that hydrolyze fructose containing polysaccharides such as inulinases (EC 3.2.1.7) and exo-inulinases (EC 3.2.1.80), levanases (EC 3.2.1.65) and β-2,6-fructan 6-levanbiohydrolases(EC 3.2.1.64), fructan β-(2,1)-fructosidase/1-exohydrolase (EC 3.2.1.153) or fructan β-(2,6)-fructosidase/6-exohydrolases (EC 3.2.1.154), as well as enzymes displaying transglycosylating activities such as sucrose:sucrose 1-fructosyltransferases (EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (EC 2.4.1.100), sucrose:fructan 6-fructosyltransferase (EC 2.4.1.10), fructan:fructan 6G-fructosyltransferase (EC 2.4.1.243) and levan fructosyltransferases (EC 2.4.1.-).

== Kinetics and Mechanism ==
Family GH32 enzymes are [[retaining]] enzymes, as first shown by Koshland and Stein by performing the reaction in <sup>18</sup>O-labeled water and determining the <sup>18</sup>O content of the products <cite>2</cite>. The transfructosylation activity (a type of [[transglycosylation]] activity) observed for invertase in this reaction indicated that the enzyme operates with a molecular mechanism leading to overall retention of the anomeric configuration <cite>2</cite>.

== Catalytic Residues ==
The two invariant residues, responsible for the catalytic reaction in family GH32 enzymes, have first been identified experimentally in yeast invertase as an aspartate located close to the N-terminus acting as the [[catalytic nucleophile]] <cite>3</cite> and a glutamate acting as the [[general acid/base]] <cite>4</cite>.

== Three-dimensional structures ==
Several three dimensional structures of family GH32 enzymes have been solved so far. The first crystal structure was reported for the bacterial β-fructosidase from ''Thermotoga maritima'' <cite>5</cite>. Further crystal structures of enzymes and their substrate-complexes have been solved for two plant enzymes (cell wall invertase <cite>6</cite> and fructan 1-exohydrolase <cite>7</cite> ), as well as one fungal exo-inulinase <cite>8</cite>. The core of the structure consists of a five-bladed β-propeller appended to a β-sandwich, consisting of two sheets of six β-strands. Although sequence similarity is low within the sandwich modules, all family GH32 members contain such a module. A structural relationship of the catalytic core module exists to family [[GH68]] (also member of [http://www.cazy.org/fam/acc_GH.html#table Clan GH-J]) and family [[GH43]], as predicted by detailed sequence analysis <cite>9</cite>. All three enzyme families display a five bladed β-propeller fold.

== Family Firsts ==
;First sterochemistry determination: ''Saccharomyces cerevisiae'' invertase <cite>2</cite>.
;First [[catalytic nucleophile]] identification: ''Saccharomyces cerevisiae'' invertase <cite>3</cite>
;First [[general acid/base]] residue identification: ''Saccharomyces cerevisiae'' invertase <cite>4</cite>
;First 3-D structure: bacterial β-fructosidase from ''Thermotoga maritima'' by X-ray crystallography (PDB ID [{{PDBlink}}1uyp 1uyp]) <cite>5</cite>

== References ==
<biblio>
#1 O'Sullivan, C., and Tompson, F. W. (1890) J. Chem. Soc. 57, 854-870
#2 pmid=13174523
#3 pmid=2113524
#4 pmid=8662946
#5 pmid=14973124
#6 pmid=17139091
#7 pmid=15659099
#8 pmid=15522299
#9 pmid=11093261

</biblio>

[[Category:Glycoside Hydrolase Families|GH032]]

User:Wim Van den Ende

2010-01-07T18:12:07Z

Wim Van den Ende: Created page with 'This is the user page of '''Wim Van den Ende'''. I am a permanent researcher at the Lab of Molecular Plant Physiology, KULeuven, Belgium. I am an agronomical engineer and a plan…'

This is the user page of '''Wim Van den Ende'''. I am a permanent researcher at the Lab of Molecular Plant Physiology, KULeuven, Belgium.

I am an agronomical engineer and a plant physiologist mainly focusing on fructan, sucrose and RFO metabolisms. Recently I became fascinated in the working mechanisms and different substrate specificities within glycoside hydrolase families GH32, GH68, GH27 and GH36.

My other research topics include:
*Regulatory role of defect invertases in plants
*Isolation of sucrose sensors
*Stress tolerance mechanisms in plants
*Rational enzym design and sugar docking
*Sugars as antioxidants
*Sugar signalling and source-sink relationships
*Connections between sugars, ascorbate and ROS in mitochondria
*Prebiotic compounds and functional food
*Mechanisms in plant development

File:Example.jpg

2010-01-07T18:08:07Z

Wim Van den Ende:

File:Example.jpg

2010-01-07T17:53:50Z

Wim Van den Ende: