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Difference between revisions of "Glycoside Hydrolase Family 75"

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* [[Author]]: [[User:Ryszard Brzezinski|Ryszard Brzezinski]]
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|-
 
|-
 
|'''Clan'''     
 
|'''Clan'''     
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|GH-x
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|Not assigned
 
|-
 
|-
 
|'''Mechanism'''
 
|'''Mechanism'''
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|inverting
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|Inverting
 
|-
 
|-
 
|'''Active site residues'''
 
|'''Active site residues'''
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|known/not known
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|Inferred
 
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|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
 
|{{Hl2}} colspan="2" align="center" |'''CAZy DB link'''
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== Substrate specificities ==
 
== Substrate specificities ==
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Glycoside hydrolases of family 75 include both eukaryotic (essentially fungal) and prokaryotic proteins. They have so far been characterized only from fimanetous fungi. They are primarily of beta-1,4-chitosanases with endo-splitting activity <cite>Shimosaka1993 Cheng2000</cite>.
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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 ==
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Family GH46 enzymes utilize an inverting mechanism as shown by NMR <cite>Chend2006</cite>.
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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>.
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−
 
 
  
 
== Catalytic Residues ==
 
== Catalytic Residues ==
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Content is to be added here.
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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.
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== Three-dimensional structures ==
 
== Three-dimensional structures ==
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Content is to be added here.
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No three-dimensional structure has been solved for this family.
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This is an example of how to make references to a journal article <cite>Comfort2007</cite>. (See the References section below).  Multiple references can go in the same place like this <cite>Comfort2007 He1999</cite>.  You can even cite books using just the ISBN <cite>StickWilliams</cite>.  References that are not in PubMed can be typed in by hand <cite>Sinnott1990</cite>.
 
  
 
== Family Firsts ==
 
== Family Firsts ==
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;First stereochemistry determination: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>Comfort2007</cite>.
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;First primary structure determination: Chitosanase from ''Fusarium solani'' f. sp. ''phaseoli'' <cite>Shimosaka1996</cite>.
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;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>Sinnott1990</cite>.
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;First stereochemistry determination: Chitosanase from ''Aspergillus fumigatus'' <cite>Cheng2006</cite>.
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;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>He1999</cite>.
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;First catalytic nucleophile identification: Not yet identified.
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;First 3-D structure: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>StickWilliams</cite>.
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;First general acid/base residue identification: Not yet identified.
 +
;First 3-D structure: Not yet determined.
  
 
== References ==
 
== References ==
 
<biblio>
 
<biblio>
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#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.
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#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
−
#Comfort2007 pmid=17323919
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#Cheng2006 pmid=16330537
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#He1999 pmid=9312086
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#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.
−
#StickWilliams isbn=978-0-240-52118-3
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#Shimosaka2005 pmid=16384794
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#Sinnott1990 Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. [http://dx.doi.org/10.1021/cr00105a006 DOI: 10.1021/cr00105a006]
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 +
 
 
</biblio>
 
</biblio>
  

Latest revision as of 14:16, 18 December 2021

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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.

Glycoside Hydrolase Family GH75
Clan Not assigned
Mechanism Inverting
Active site residues Inferred
CAZy DB link
http://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

  1. 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.

    [Shimosaka1993]
  2. 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 | PubMed ID:11115392 [Cheng2000]
  3. 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 | PubMed ID:16330537 [Cheng2006]
  4. 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 | PubMed ID:16384794 [Shimosaka2005]

  5. 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.

    [Shimosaka1996]

All Medline abstracts: PubMed

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