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Difference between revisions of "Glycoside Hydrolase Family 7"
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== Substrate specificities == | == Substrate specificities == | ||
| − | [[Glycoside hydrolases]] of family 7 cleave β-1,4 glycosidic bonds in cellulose. Several members also show activity on xylan. The substrate specificities found in GH7 are: ''[[endo]]''-1,4-β-glucanase (EC 3.2.1.4) | + | Most [[Glycoside hydrolases]] of family 7 cleave β-1,4 glycosidic bonds in cellulose/β-1,4-glucans. Several members also show activity on xylan. The substrate specificities found in GH7 are: ''[[endo]]''-1,4-β-glucanase (EC 3.2.1.4), [reducing end-acting] cellobiohydrolase (EC 3.2.1.-), chitosanase (EC 3.2.1.132) and ''[[endo]]''-1,3-1,4-β-glucanase (EC 3.2.1.73). |
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== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
| − | + | Family 7 enzymes are [[retaining]] enzymes, as first shown by NMR <cite>Knowles1988</cite> on Cellobiohydrolase I, CBH I, later called Cel7A, from the fungus ''Trichoderma reesei'', which has later been identified as a clonal derivative of ''Hypocrea jecorina''. | |
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== Catalytic Residues == | == Catalytic Residues == | ||
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== Family Firsts == | == Family Firsts == | ||
| − | ;First sterochemistry determination: | + | ;First sterochemistry determination: ''Hypocrea jecorina'' cellobiohydrolase Cel7A by NMR <cite>Knowles1988</cite>. |
;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>MikesClassic</cite>. | ;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>MikesClassic</cite>. | ||
;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>He1999</cite>. | ;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 sentence) explanation <cite>He1999</cite>. | ||
| − | ;First 3-D structure: | + | ;First 3-D structure: First cellobiohydrolase was ''Hypocrea jecorina'' Cel7A (CBH I; [http://www.rcsb.org/pdb/explore/explore.do?structureId=1CEL PDB 1cel]) <cite>Divne1994</cite>. First ''[[endo]]''-1,4-β-glucanase was Endoglucanase I (EG I, Cel7B) from ''Fusarium oxysporum'' ([http://www.rcsb.org/pdb/explore/explore.do?structureId=1BYH PDB 1byh]) <cite>Sulzenbacher1996</cite>, both by X-ray crystallography. |
== References == | == References == | ||
<biblio> | <biblio> | ||
| − | # | + | #Knowles1988 Jonathan K. C. Knowles, J.K.C., Lehtovaara, P., Murray, M. and Sinnott, M.L. (1988) Stereochemical course of the action of the cellobioside hydrolases I and II of ''Trichoderma reesei''. J. Chem. Soc., Chem. Commun., 1988, 1401-1402. [http://dx.doi.org/10.1039/C39880001401 DOI: 10.1039/C39880001401] |
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| + | #Divne1994 pmid=8036495 | ||
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| + | #Sulzenbacher1996 pmid=8952478 | ||
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#He1999 pmid=9312086 | #He1999 pmid=9312086 | ||
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#3 isbn=978-0-240-52118-3 | #3 isbn=978-0-240-52118-3 | ||
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#MikesClassic 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] | #MikesClassic 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] | ||
Revision as of 14:50, 24 February 2010
This page is currently under construction. This means that the Responsible Curator has deemed that the page's content is not quite up to CAZypedia's standards for full public consumption. All information should be considered to be under revision and may be subject to major changes.
- Author: ^^^Jerry Stahlberg^^^
- Responsible Curator: ^^^Jerry Stahlberg^^^
| Glycoside Hydrolase Family 7 | |
| Clan | GH-B |
| Mechanism | retaining |
| Active site residues | known |
| CAZy DB link | |
| http://www.cazy.org/fam/GH7.html | |
Substrate specificities
Most Glycoside hydrolases of family 7 cleave β-1,4 glycosidic bonds in cellulose/β-1,4-glucans. Several members also show activity on xylan. The substrate specificities found in GH7 are: endo-1,4-β-glucanase (EC 3.2.1.4), [reducing end-acting] cellobiohydrolase (EC 3.2.1.-), chitosanase (EC 3.2.1.132) and endo-1,3-1,4-β-glucanase (EC 3.2.1.73).
Kinetics and Mechanism
Family 7 enzymes are retaining enzymes, as first shown by NMR [1] on Cellobiohydrolase I, CBH I, later called Cel7A, from the fungus Trichoderma reesei, which has later been identified as a clonal derivative of Hypocrea jecorina.
Catalytic Residues
Content is to be added here.
Three-dimensional structures
Content is to be added here.
Family Firsts
- First sterochemistry determination
- Hypocrea jecorina cellobiohydrolase Cel7A by NMR [1].
- First catalytic nucleophile identification
- Cite some reference here, with a short (1-2 sentence) explanation [2].
- First general acid/base residue identification
- Cite some reference here, with a short (1-2 sentence) explanation [3].
- First 3-D structure
- First cellobiohydrolase was Hypocrea jecorina Cel7A (CBH I; PDB 1cel) [4]. First endo-1,4-β-glucanase was Endoglucanase I (EG I, Cel7B) from Fusarium oxysporum (PDB 1byh) [5], both by X-ray crystallography.
References
-
Jonathan K. C. Knowles, J.K.C., Lehtovaara, P., Murray, M. and Sinnott, M.L. (1988) Stereochemical course of the action of the cellobioside hydrolases I and II of Trichoderma reesei. J. Chem. Soc., Chem. Commun., 1988, 1401-1402. DOI: 10.1039/C39880001401
-
Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. DOI: 10.1021/cr00105a006
- He S and Withers SG. (1997). Assignment of sweet almond beta-glucosidase as a family 1 glycosidase and identification of its active site nucleophile. J Biol Chem. 1997;272(40):24864-7. DOI:10.1074/jbc.272.40.24864 |
- Divne C, Ståhlberg J, Reinikainen T, Ruohonen L, Pettersson G, Knowles JK, Teeri TT, and Jones TA. (1994). The three-dimensional crystal structure of the catalytic core of cellobiohydrolase I from Trichoderma reesei. Science. 1994;265(5171):524-8. DOI:10.1126/science.8036495 |
- Sulzenbacher G, Driguez H, Henrissat B, Schülein M, and Davies GJ. (1996). Structure of the Fusarium oxysporum endoglucanase I with a nonhydrolyzable substrate analogue: substrate distortion gives rise to the preferred axial orientation for the leaving group. Biochemistry. 1996;35(48):15280-7. DOI:10.1021/bi961946h |
- Robert V. Stick and Spencer J. Williams. (2009) Carbohydrates. Elsevier Science.