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Difference between revisions of "Glycoside Hydrolase Family 75"
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| − | + | * [[Author]]: [[User:Ryszard Brzezinski|Ryszard Brzezinski]] | |
| − | * [[Author]]: | + | * [[Responsible Curator]]: [[User:Ryszard Brzezinski|Ryszard Brzezinski]] |
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|- | |- | ||
|'''Mechanism''' | |'''Mechanism''' | ||
| − | | | + | |Inverting |
|- | |- | ||
|'''Active site residues''' | |'''Active site residues''' | ||
| − | | | + | |Inferred |
|- | |- | ||
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link''' | |{{Hl2}} colspan="2" align="center" |'''CAZy DB link''' | ||
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== Substrate specificities == | == Substrate specificities == | ||
| − | Glycoside hydrolases of family 75 include both eukaryotic (essentially fungal) and prokaryotic proteins. They have so far been characterized only from filamentous fungi. They are | + | Glycoside hydrolases of family 75 include both eukaryotic (essentially fungal) and prokaryotic proteins. They have so far been characterized only from filamentous fungi. They are beta-1,4-chitosanases with endo-splitting activity <cite>Shimosaka1993 Cheng2000</cite>. The analysis of the final product of hydrolysis of partially ''N''-deacetylated chitosan by the GH75 chitosanase from ''Aspergillus fumigatus'' suggests that this enzyme cleaves preferentially GlcN-GlcN and GlcNAc-GlcN links in the polysaccharide chain <cite>Cheng2006</cite>. |
== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
| − | Family GH46 enzymes | + | Family GH46 enzymes are classified as inverting enzymes. This has been shown by <sup>1</sup>H NMR for the enzyme from ''Aspergillus fumigatus'' using chitosan as substrate <cite>Cheng2006</cite>. |
| − | |||
| − | |||
== Catalytic Residues == | == Catalytic Residues == | ||
| − | + | A site-directed mutagenesis study performed on the enzyme from ''Fusarium solani'' (expressed as a recombinant protein in ''Saccharomyces cerevisiae'') showed that Asp175 and Glu188 are essential for catalysis <cite>Shimosaka2005</cite>. This was confirmed by a study on the chitosanase from ''Aspergillus fumigatus'' (expressed as a recombinant protein in ''Escherichia coli'') showing that the corresponding residues Asp160 and Glu169 are essential for catalysis <cite>Cheng2006</cite>. Both residues are strictly conserved among eukaryotic and prokaryotic GH75 family members. | |
| − | |||
== Three-dimensional structures == | == Three-dimensional structures == | ||
| − | + | No three-dimensional structure has been solved for this family. | |
| − | |||
| − | |||
== Family Firsts == | == Family Firsts == | ||
| − | ;First | + | ;First primary structure determination: Chitosanase from ''Fusarium solani'' f. sp. ''phaseoli'' <cite>Shimosaka1996</cite>. |
| − | ;First | + | ;First stereochemistry determination: Chitosanase from ''Aspergillus fumigatus'' <cite>Cheng2006</cite>. |
| − | ;First general acid/base residue identification: | + | ;First catalytic nucleophile identification: Not yet identified. |
| − | ;First 3-D structure: | + | ;First general acid/base residue identification: Not yet identified. |
| + | ;First 3-D structure: Not yet determined. | ||
== References == | == References == | ||
<biblio> | <biblio> | ||
| − | #Shimosaka1993 Shimosaka M, Nogawa M, Ohno Y, and Okazaki M. Chitosanase from the pathogenic fungus, ''Fusarium solani'' f.sp. ''phaseoli'' - purification and some properties. Biosci. Biotech. Biochem. 57, 231-235. | + | #Shimosaka1993 Shimosaka M, Nogawa M, Ohno Y, and Okazaki M. Chitosanase from the pathogenic fungus, ''Fusarium solani'' f.sp. ''phaseoli'' - purification and some properties. Biosci. Biotech. Biochem. 1993 57, 231-235. |
#Cheng2000 pmid=11115392 | #Cheng2000 pmid=11115392 | ||
#Cheng2006 pmid=16330537 | #Cheng2006 pmid=16330537 | ||
| + | #Shimosaka1996 Shimosaka M, Kumehara M, Zhang X-Y, Nogawa M, and Okazaki M. Cloning and characterization of a chitosanase gene from the plant pathogenic fungus Fusarium solani. J. Ferment. Bioeng. 1996 82, 426-431. | ||
| + | #Shimosaka2005 pmid=16384794 | ||
Latest revision as of 13:16, 18 December 2021
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| Glycoside Hydrolase Family GH75 | |
| Clan | Not assigned |
| Mechanism | Inverting |
| Active site residues | Inferred |
| CAZy DB link | |
| https://www.cazy.org/GH75.html | |
Substrate specificities
Glycoside hydrolases of family 75 include both eukaryotic (essentially fungal) and prokaryotic proteins. They have so far been characterized only from filamentous fungi. They are beta-1,4-chitosanases with endo-splitting activity [1, 2]. The analysis of the final product of hydrolysis of partially N-deacetylated chitosan by the GH75 chitosanase from Aspergillus fumigatus suggests that this enzyme cleaves preferentially GlcN-GlcN and GlcNAc-GlcN links in the polysaccharide chain [3].
Kinetics and Mechanism
Family GH46 enzymes are classified as inverting enzymes. This has been shown by 1H NMR for the enzyme from Aspergillus fumigatus using chitosan as substrate [3].
Catalytic Residues
A site-directed mutagenesis study performed on the enzyme from Fusarium solani (expressed as a recombinant protein in Saccharomyces cerevisiae) showed that Asp175 and Glu188 are essential for catalysis [4]. This was confirmed by a study on the chitosanase from Aspergillus fumigatus (expressed as a recombinant protein in Escherichia coli) showing that the corresponding residues Asp160 and Glu169 are essential for catalysis [3]. Both residues are strictly conserved among eukaryotic and prokaryotic GH75 family members.
Three-dimensional structures
No three-dimensional structure has been solved for this family.
Family Firsts
- First primary structure determination
- Chitosanase from Fusarium solani f. sp. phaseoli [5].
- First stereochemistry determination
- Chitosanase from Aspergillus fumigatus [3].
- First catalytic nucleophile identification
- Not yet identified.
- First general acid/base residue identification
- Not yet identified.
- First 3-D structure
- Not yet determined.
References
-
Shimosaka M, Nogawa M, Ohno Y, and Okazaki M. Chitosanase from the pathogenic fungus, Fusarium solani f.sp. phaseoli - purification and some properties. Biosci. Biotech. Biochem. 1993 57, 231-235.
- Cheng CY and Li YK. (2000). An Aspergillus chitosanase with potential for large-scale preparation of chitosan oligosaccharides. Biotechnol Appl Biochem. 2000;32(3):197-203. DOI:10.1042/ba20000063 |
- Cheng CY, Chang CH, Wu YJ, and Li YK. (2006). Exploration of glycosyl hydrolase family 75, a chitosanase from Aspergillus fumigatus. J Biol Chem. 2006;281(6):3137-44. DOI:10.1074/jbc.M512506200 |
- Shimosaka M, Sato K, Nishiwaki N, Miyazawa T, and Okazaki M. (2005). Analysis of essential carboxylic amino acid residues for catalytic activity of fungal chitosanases by site-directed mutagenesis. J Biosci Bioeng. 2005;100(5):545-50. DOI:10.1263/jbb.100.545 |
-
Shimosaka M, Kumehara M, Zhang X-Y, Nogawa M, and Okazaki M. Cloning and characterization of a chitosanase gene from the plant pathogenic fungus Fusarium solani. J. Ferment. Bioeng. 1996 82, 426-431.