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Difference between revisions of "Glycosyltransferases"
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== Common sugar nucleotide donors == | == Common sugar nucleotide donors == | ||
Revision as of 17:38, 12 August 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: Spencer Williams
- Responsible Curator: Spencer Williams
Overview
Glycosyltransferases are enzymes that catalyze the formation of the glycosidic linkage to form a glycoside. These enzymes utilize 'activated' sugar phosphates as glycosyl donors, and catalyze glycosyl group transfer to a nucleophilic group, usually an alcohol. The product of glycosyl transfer may be an O-, N-, S-, or C-glycoside; the glycoside may be part of a monosaccharide glycoside, oligosaccharide, or polysaccharide ([1, 2, 3, 4, 5]).
Donors
Glycosyltransferases can utilize a range of donor species. Sugar mono- or diphosphonucleotides are sometimes termed Leloir donors (after Nobel prize winner, Luis Leloir); the corresponding enzymes are termed Leloir donors.
Glycosyltransferases that utilize non-nucleotide donors, which may be polyprenol pyrophosphates, polyprenol phosphates, sugar-1-phosphates, or sugar-1-pyrophosphates, are termed non-Leloir glycosyltransferases.
Mechanism
Glycosyltransferases catalyze the transfer of glycosyl groups to a nucleophilic acceptor with either retention or inversion of configuration at the anomeric centre. This allows the classification of glycosyltransferases as either retaining or inverting enzymes.
Inverting glycosyltransferases
Structural and kinetic data for inverting glycosyltransferases support a mechanism that proceeds through a single nucleophilic substitution step, facilitated by an enzymic general base catalyst. The transition state is believed to possess substantial oxocarbenium ion character.
Retaining glycosyltransferases
3-D folds
<applet load=1h7l size="300" color="white" frame="true" spin="on" caption="SpsA from Bacillus subtilus, PDB=1h7l" align="right" />
Role of metals
Common sugar nucleotide donors
References
- Lairson LL, Henrissat B, Davies GJ, and Withers SG. (2008). Glycosyltransferases: structures, functions, and mechanisms. Annu Rev Biochem. 2008;77:521-55. DOI:10.1146/annurev.biochem.76.061005.092322 |
- Coutinho PM, Deleury E, Davies GJ, and Henrissat B. (2003). An evolving hierarchical family classification for glycosyltransferases. J Mol Biol. 2003;328(2):307-17. DOI:10.1016/s0022-2836(03)00307-3 |
- Campbell JA, Davies GJ, Bulone V, and Henrissat B. (1997). A classification of nucleotide-diphospho-sugar glycosyltransferases based on amino acid sequence similarities. Biochem J. 1997;326 ( Pt 3)(Pt 3):929-39. DOI:10.1042/bj3260929u |
- Claus-Wilhelm von der Lieth, Thomas Luetteke, and Martin Frank. (2010-01-19) Bioinformatics for Glycobiology and Glycomics: An Introduction. Wiley.
Chapter 5: Coutinho PM, Rancurel C, Stam M, Bernard T, Couto FM, Danchin EGJ, Henrissat B. "Carbohydrate-active Enzymes Database: Principles and Classification of Glycosyltransferases."