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Difference between revisions of "Glycoside Hydrolase Family 45"
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== Kinetics and Mechanism == | == Kinetics and Mechanism == | ||
| − | The enzymes act with inversion of anomeric configuration to generate the alpha-D glucoside as product. Based upon the structure of the ''Humicola insolens'' endoglucanase V (now known as Cel45) it was concluded that Asp121 acted as the catalytic acid (implied by its hydrogen bonding to the glycosidic oxygen) and that the most likely catalytic base would be Asp10, appropriately positioned "below" the sugar plane. As with many inverting enzymes the base assignment is less secure than that of the acid. | + | The enzymes act with inversion of anomeric configuration to generate the alpha-D glucoside as product. Based upon the structure of the ''Humicola insolens'' endoglucanase V (now known as Cel45)<cite>Davies1993</cite><cite>Davies1995</cite> it was concluded that Asp121 acted as the catalytic acid (implied by its hydrogen bonding to the glycosidic oxygen) and that the most likely catalytic base would be Asp10, appropriately positioned "below" the sugar plane. As with many inverting enzymes the base assignment is less secure than that of the acid. |
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;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>4</cite>. | ;First catalytic nucleophile identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>4</cite>. | ||
;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>2</cite>. | ;First general acid/base residue identification: Cite some reference here, with a ''short'' (1-2 senetence) explanation <cite>2</cite>. | ||
| − | ;First 3-D structure: The Humicola insolens EGV (now Cel45) by the Davies group <cite> | + | ;First 3-D structure: The Humicola insolens EGV (now Cel45) by the Davies group <cite>Davies1993</cite>. |
== References == | == References == | ||
<biblio> | <biblio> | ||
| − | # | + | #Davies1993 pmid=8377830 |
| − | # | + | #Davies1995 pmid=8519779 |
#3 isbn=978-0-240-52118-3 | #3 isbn=978-0-240-52118-3 | ||
#4 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] | #4 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 11:25, 5 October 2009
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: ^^^Gideon Davies^^^
- Responsible Curator: ^^^Gideon Davies^^^
| Glycoside Hydrolase Family GH45 | |
| Clan | none |
| Mechanism | inverting |
| Active site residues | known (but see discussion) |
| CAZy DB link | |
| http://www.cazy.org/fam/GH45.html | |
Substrate specificities
Endoglucanases (EC 3.2.1.4). Mainly the hydrolysis of soluble beta 1,4 glucans.
Kinetics and Mechanism
The enzymes act with inversion of anomeric configuration to generate the alpha-D glucoside as product. Based upon the structure of the Humicola insolens endoglucanase V (now known as Cel45)[1][2] it was concluded that Asp121 acted as the catalytic acid (implied by its hydrogen bonding to the glycosidic oxygen) and that the most likely catalytic base would be Asp10, appropriately positioned "below" the sugar plane. As with many inverting enzymes the base assignment is less secure than that of the acid.
Catalytic Residues
Content is to be added here.
Three-dimensional structures
Content is to be added here.
Family Firsts
- First sterochemistry determination
- Cite some reference here, with a short (1-2 senetence) explanation [3].
- First catalytic nucleophile identification
- Cite some reference here, with a short (1-2 senetence) explanation [4].
- First general acid/base residue identification
- Cite some reference here, with a short (1-2 senetence) explanation [5].
- First 3-D structure
- The Humicola insolens EGV (now Cel45) by the Davies group [1].
References
- Davies GJ, Dodson GG, Hubbard RE, Tolley SP, Dauter Z, Wilson KS, Hjort C, Mikkelsen JM, Rasmussen G, and Schülein M. (1993). Structure and function of endoglucanase V. Nature. 1993;365(6444):362-4. DOI:10.1038/365362a0 |
- Davies GJ, Tolley SP, Henrissat B, Hjort C, and Schülein M. (1995). Structures of oligosaccharide-bound forms of the endoglucanase V from Humicola insolens at 1.9 A resolution. Biochemistry. 1995;34(49):16210-20. DOI:10.1021/bi00049a037 |
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Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. DOI: 10.1021/cr00105a006
[[Category:Glycoside Hydrolase Families|GHnnn]]