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Difference between revisions of "Glycoside Hydrolase Family 80"
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== Substrate specificities == | == Substrate specificities == | ||
| − | Glycoside | + | Glycoside hydrolase family GH80 is comprised of endo-acting beta-1,4-chitosanases of bacterial origin. The first characterized member was from a proteobacterium <cite>Park1999</cite> belonging to the Bacteroidetes/Chlorobi group <cite>Matsuda2001 Yi2004</cite>. At present (July 2011), GH80 is very small family, comprised of fewer than 20 members. |
| − | |||
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| + | Characterized GH80 members do not hydrolyze chitin or cellulose <cite>Park1999 Yi2004</cite>, and for one member, the chitosan hexa-oligosaccharide (GlcN)<sub>6</sub> is preferentially hydrolyzed into two molecules of the trisaccharide <cite>Shimono2002</cite>. | ||
== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
| − | + | The stereochemistry of the hydrolytic reaction catalyzed by GH80 members has not yet been studied. However, sequence similarity with members of [[Clan]] GH-I suggests that these enzymes may operate with inversion of the anomeric configuration (see [[#Catalytic Residues]], below) | |
| + | == Catalytic Residues == | ||
| + | The chitosanases from family GH80 share a PROSITE signature motif with the chitosanases from family GH46 <cite>Tremblay2000 Sigrist2010</cite>. | ||
| − | |||
A site-directed mutagenesis study of the chitosanase A from ''Matsuebacter chitosanotabidus'' 3001 (new name: ''Mitsuaria chitosanitabida'' <cite>Amakata2005</cite>) identified two residues as essentiel for catalysis: Glu-121 (in the sequence YP<u>E</u>NG)and Glu-141 (in the sequence DY<u>E</u>AA) <cite>Shimono2002</cite>. | A site-directed mutagenesis study of the chitosanase A from ''Matsuebacter chitosanotabidus'' 3001 (new name: ''Mitsuaria chitosanitabida'' <cite>Amakata2005</cite>) identified two residues as essentiel for catalysis: Glu-121 (in the sequence YP<u>E</u>NG)and Glu-141 (in the sequence DY<u>E</u>AA) <cite>Shimono2002</cite>. | ||
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== Three-dimensional structures == | == Three-dimensional structures == | ||
No three-dimensional structure has been solved for this family. | No three-dimensional structure has been solved for this family. | ||
| − | |||
== Family Firsts == | == Family Firsts == | ||
Revision as of 06:00, 18 July 2011
This page has been approved by the Responsible Curator as essentially complete. CAZypedia is a living document, so further improvement of this page is still possible. If you would like to suggest an addition or correction, please contact the page's Responsible Curator directly by e-mail.
- Author: ^^^Ryszard Brzezinski^^^
- Responsible Curator: ^^^Ryszard Brzezinski^^^
| Glycoside Hydrolase Family GH80 | |
| Clan | GH-I |
| Mechanism | not determined |
| Active site residues | inferred |
| CAZy DB link | |
| http://www.cazy.org/GH80.html | |
Substrate specificities
Glycoside hydrolase family GH80 is comprised of endo-acting beta-1,4-chitosanases of bacterial origin. The first characterized member was from a proteobacterium [1] belonging to the Bacteroidetes/Chlorobi group [2, 3]. At present (July 2011), GH80 is very small family, comprised of fewer than 20 members.
Characterized GH80 members do not hydrolyze chitin or cellulose [1, 3], and for one member, the chitosan hexa-oligosaccharide (GlcN)6 is preferentially hydrolyzed into two molecules of the trisaccharide [4].
Kinetics and Mechanism
The stereochemistry of the hydrolytic reaction catalyzed by GH80 members has not yet been studied. However, sequence similarity with members of Clan GH-I suggests that these enzymes may operate with inversion of the anomeric configuration (see #Catalytic Residues, below)
Catalytic Residues
The chitosanases from family GH80 share a PROSITE signature motif with the chitosanases from family GH46 [5, 6].
A site-directed mutagenesis study of the chitosanase A from Matsuebacter chitosanotabidus 3001 (new name: Mitsuaria chitosanitabida [7]) identified two residues as essentiel for catalysis: Glu-121 (in the sequence YPENG)and Glu-141 (in the sequence DYEAA) [4].
Three-dimensional structures
No three-dimensional structure has been solved for this family.
Family Firsts
- First primary sequence determination
- Chitosanase ChoA from Matsuebacter chitosanotabidus 3001 (now Mitsuaria chitosanitabida) [1, 7]
- First stereochemistry determination
- Not yet determined
- First catalytic nucleophile identification
- Not yet identified
- First general acid/base residue identification
- Not yet identified
- First 3-D structure
- Not yet determined
References
<biblio>
- Park1999 pmid=10542164
- Matsuda2001 Matsuda, Y., Iida, I., Shinogi, T., Kakutani, K., Nonomura, T., Toyoda, H. (2001) In vitro suppression of mycelial growth of Fusarium oxysporum by extracellular chitosanase of Sphingobacterium multivorum and cloning of the chitosanase gene csnSM1. J. Gen. Plant Pathol. 67, 318-324.
- Yi2004 Yi, J.-H., Jang, H.-K., Lee, S.-J., Lee, K.-E., Choi, S.-G. (2004) Purification and properties of chitosanase from chitinolytic beta-Proteobacterium KNU3. J. Microbiol. Biotechnol. 14, 337-343.
- Shimono2002 pmid=11754739
- Tremblay2000 pmid=11068683
- Sigrist2010 pmid=19858104
- Amakata2005 pmid=16166689