Glycoside Hydrolase Family 72 - Revision history

Harry Brumer: Text replacement - "\^\^\^(.*)\^\^\^" to "$1"

2021-12-18T21:19:20Z

Text replacement - "\^\^\^(.*)\^\^\^" to "$1"

Spencer Williams: /* Family Firsts */

2016-01-02T07:39:12Z

Family Firsts

Spencer Williams: /* Family Firsts */

2016-01-02T07:38:52Z

Family Firsts

Spencer Williams: /* Three-dimensional structures */

2016-01-02T07:38:25Z

Three-dimensional structures

Spencer Williams: /* Catalytic Residues */

2016-01-02T07:37:51Z

Catalytic Residues

Spencer Williams: /* Catalytic Residues */

2016-01-02T07:36:49Z

Catalytic Residues

Spencer Williams: /* Three-dimensional structures */

2016-01-02T03:33:06Z

Three-dimensional structures

Spencer Williams: /* Catalytic Residues */

2016-01-02T03:32:21Z

Catalytic Residues

Spencer Williams at 03:31, 2 January 2016

2016-01-02T03:31:12Z

Spencer Williams at 03:25, 2 January 2016

2016-01-02T03:25:42Z

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 {{CuratorApproved}}
-* [[Author]]s: ^^^Ramon Hurtado-Guerrero^^^ and ^^^Thierry Fontaine^^^
+* [[Author]]s: [[User:Ramon Hurtado-Guerrero|Ramon Hurtado-Guerrero]] and [[User:Thierry Fontaine|Thierry Fontaine]]
-* [[Responsible Curator]]:  ^^^Bernard Henrissat^^^
+* [[Responsible Curator]]:  [[User:Bernard Henrissat|Bernard Henrissat]]
 ----

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 == Family Firsts ==
 ;First stereochemistry determination:
-β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Hartland1996</cite>
+β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Hartland1996</cite>.
 ;First catalytic nucleophile identification:
-Shown in the β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Mouyna2000b</cite>
+Shown in the β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Mouyna2000b</cite>.
 ;First general acid/base residue identification:
-Shown in the β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Mouyna2000b</cite>
+Shown in the β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Mouyna2000b</cite>.
 ;First 3-D structure:
-ScGas2 crystal structure  <cite>Hurtado-Guerrero2009</cite>
+ScGas2 crystal structure  <cite>Hurtado-Guerrero2009</cite>.
 == References ==

@@ Line 47: / Line 47: @@
 ;First general acid/base residue identification:
 Shown in the β-1,3-glucanosyltransglycosylase (Gel1p) from ''Aspergillus fumigatus'' <cite>Mouyna2000b</cite>
-;First 3-D structure: ScGas2 crystal structure  <cite>Hurtado-Guerrero2009</cite>
+;First 3-D structure:
 == References ==

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 == Three-dimensional structures ==
-[[File:Gas2FINAL.jpg|thumb|300px|right|'''Figure 1.''' Crystal structure of ''Sc''Gas2 ([{{PDBlink}}2w62 PDB ID 2w62]).]]The first three-dimensional structures available for a GH72 member are that of ''S. cerevisiae'' ScGas2 in free form ([{{PDBlink}}2w61 PDB ID 2w61]) and in complex with carbohydrates ([{{PDBlink}}2w62 PDB ID 2w62], [{{PDBlink}}2w63 PDB ID 2w63])  (Figure 1). The enzyme folds as a (beta/alpha)<sub>8</sub> barrel similar to that prevailing in other families constituting Clan GH-A  <cite>Hurtado-Guerrero2009</cite>. The full length enzyme also harbors a [[CBM43]] module at the C-terminus. The crystal structure also showed that both domains share extensive contacts  <cite>Hurtado-Guerrero2009</cite>.
+[[File:Gas2FINAL.jpg|thumb|300px|right|'''Figure 1.''' Crystal structure of ''Sc''Gas2 ([{{PDBlink}}2w62 PDB ID 2w62]).]]The first three-dimensional structures available for a GH72 member were that of ''S. cerevisiae'' ScGas2 in free form ([{{PDBlink}}2w61 PDB ID 2w61]) and in complex with carbohydrates ([{{PDBlink}}2w62 PDB ID 2w62], [{{PDBlink}}2w63 PDB ID 2w63])  (Figure 1). The enzyme folds as a (beta/alpha)<sub>8</sub> barrel similar to that prevailing in other families constituting Clan GH-A  <cite>Hurtado-Guerrero2009</cite>. The full length enzyme also harbors a [[CBM43]] module at the C-terminus. The crystal structure also showed that both domains share extensive contacts  <cite>Hurtado-Guerrero2009</cite>.
 == Family Firsts ==

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 == Catalytic Residues ==
-Multiple sequence alignments have highlighted conserved amino acid between GH72 family members <cite>Mouyna2000b</cite>. Hydrophobic cluster analysis allowed identification of two highly conserved glutamate residues in the region comparable to the C-terminal end of strands β-4 and β-7 of ''Clostridium cellulolyticum'' endoglucanase A (a [[GH5]] member) <cite>Mouyna2000</cite>. Site-direct mutagenesis of these two glutamate residues in ''A. fumigatus'' Gel1p and ''S. cerevisiae'' Gas1p have shown their essentiality for the transglycosidase activity  <cite>Mouyna2000b Carotti2004</cite> and support that these residues are the acid-base and nucleophilic residues (Glu-160 and Glu-261, respectively, of Gel1p from ''C. albicans''). The identity of these residues was further confirmed by the resolution of the crystal structure of ''S. cerevisiae'' Gas2 (ScGas2) (see below)  <cite>Hurtado-Guerrero2009</cite>.
+Multiple sequence alignments have highlighted conserved amino acid between GH72 family members <cite>Mouyna2000b</cite>. Hydrophobic cluster analysis allowed identification of two highly conserved glutamate residues in the region comparable to the C-terminal end of strands β-4 and β-7 of ''Clostridium cellulolyticum'' endoglucanase A (a [[GH5]] member) <cite>Mouyna2000</cite>. Site-direct mutagenesis of these two glutamate residues in ''A. fumigatus'' Gel1p and ''S. cerevisiae'' Gas1p have shown their essentiality for the transglycosidase activity  <cite>Mouyna2000b Carotti2004</cite> and support the assignment of these residues as the acid-base and nucleophilic residues (Glu-160 and Glu-261, respectively, of Gel1p from ''C. albicans''). The identity of these residues was further confirmed by the resolution of the crystal structure of ''S. cerevisiae'' Gas2 (ScGas2) (see below)  <cite>Hurtado-Guerrero2009</cite>.
 == Three-dimensional structures ==

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 == Substrate specificities ==
-[[Glycoside hydrolase]] family GH72 is formed exclusively by [[transglycosylases]] of the fungal kingdom whose activity was firstly characterized in ''Aspergillus fumigatus'' <cite>Hartland1996</cite> and yeasts <cite>Mouyna2000 Carotti2004 deMedina-Redondo2008</cite>. These GPI-anchored plasma membrane enzymes elongate and remodel the β-1,3 glucan of the cell wall <cite>Mouyna2000a Mouyna2005 Gastebois2010 deMedina-Redondo2008 deMedina-Redondo2010 Ragni2007a</cite>. This activity is due to their catalytic domain is located in the external part of the plasma membrane. Two sub-families have been described for GH72 family members depending on the presence or absence of a C-terminal cysteine rich domain (carbohydrate binding domain, [[CBM43]]) in addition to the catalytic domain <cite>Ragni2007b</cite>.
+[[Glycoside hydrolase]] family GH72 is formed exclusively of [[transglycosylases]] of the fungal kingdom. Their activity was first characterized in ''Aspergillus fumigatus'' <cite>Hartland1996</cite> and yeasts <cite>Mouyna2000 Carotti2004 deMedina-Redondo2008</cite>. GH72 transglycosidases are GPI-anchored plasma membrane enzymes that elongate and remodel the 1,3-β-glucan of the cell wall <cite>Mouyna2000a Mouyna2005 Gastebois2010 deMedina-Redondo2008 deMedina-Redondo2010 Ragni2007a</cite>. The catalytic domain is located in the external part of the plasma membrane. Two sub-families have been described for GH72 family members depending on the presence or absence of a C-terminal cysteine rich domain (carbohydrate binding domain, [[CBM43]]) in addition to the catalytic domain <cite>Ragni2007b</cite>.
 == Kinetics and Mechanism ==
-The catalysis by GH72 family enzymes occurs via a classical Koshland retaining mechanism, which leads to net retention of the β-anomeric configuration of the final product. Enzymatic kinetics were determined by HPLC and showed that these enzymes are [[transglycosylases]] rather than [[glycoside hydrolases]]. These enzymes cleave internally a β-1,3-glucan molecule and transfer the newly generated reducing end to the non-reducing end of a second β-1,3-glucan molecule through a β-1,3-linkage, resulting in the elongation of the chain. The minimum size of the donor and acceptor substrates described in few fungal species are laminaridecaose and laminaripentaose, respectively <cite>Hartland1996 Mazan2011</cite>.
+Catalysis by GH72 family enzymes occurs through a [[classical Koshland retaining mechanism]], which leads to net retention of the β-anomeric configuration of the final product. Enzymatic kinetics were determined by HPLC and showed that these enzymes are [[transglycosylases]] rather than [[glycoside hydrolases]]. Fungal GH72 enzymes internally cleave a 1,3-β-glucan molecule and form a glycosyl enzyme which reacts with the non-reducing end of a second β-1,3-glucan molecule, forming a new β-1,3-glucosidic linkage, resulting in the truncation of the first chain and elongation of the second. The minimum size of the donor and acceptor substrates so far described are laminaridecaose and laminaripentaose, respectively <cite>Hartland1996 Mazan2011</cite>.
-Despite that the overall mechanisms of [[glycoside hydrolases|hydrolysis]] and [[transglycosylases|transglycosylation]] are well known, it is still unclear how [[transglycosylases]] limit or prevent hydrolysis in aqueous media, where the concentration of water is 55 M. By structural studies with different laminarioligosaccharides and enzymatic activity assays, a “base occlusion mechanism”, in which the acceptor sugar blocks the entrance of water molecules, was proposed to explain this phenomenon <cite>Hurtado-Guerrero2009</cite>.
+Despite the fact that the overall mechanisms of [[glycoside hydrolases|hydrolysis]] and [[transglycosylases|transglycosylation]] are well known, it is still unclear how [[transglycosylases]] limit or prevent hydrolysis in aqueous media, where the concentration of water is 55 M. By structural studies with different laminarioligosaccharides and enzymatic activity assays, a “base occlusion mechanism”, in which the acceptor sugar blocks the entrance of water molecules, was proposed to explain this phenomenon <cite>Hurtado-Guerrero2009</cite>.
 == Catalytic Residues ==