Glycosyltransferase Family 38

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: ^^^Warren Wakarchuk^^^
• Responsible Curator: ^^^Warren Wakarchuk^^^

---

Glycosyltransferase Family GT38
Clan	GT-B
Mechanisn	inverting
Active site residues	known
CAZy DB link
https://www.cazy.org/GT38.html

Substrate specificities

Members of GT-38 are the bacterial polysialyltransferases (polySTs), which catalyze the addition of sialic acids from the activated sugar donor, CMP-sialic acid (CMP-Neu5Ac), to the nonreducing end of the growing polySia chain (PMID: 7972078 Cho and Troy 1994; Nakayama and Fukuda 1996). These enzymes build the polymer as a capsular polysaccharide on a specialized poly-β-KDO modified lyso-phosphatidyl glycerol anchor in the membrane of Gram negative bacteria PMID: 23610430. Bacterial polySia capsules exist in three different flavours: Escherichia coli K1, Neisseria meningitidis serotype B, Moraxella nonliquefaciens, and Mannheimia haemolytica A2 synthesize α-2,8-linked polySia whereas N. meningitidis serotype C produces a α-2,9-linked polymer and E. coli K92 produces polymers with alternating α-2,8 and α-2,9 linkages PMID: 10052589 PMID: 1898915 PMID: 64575. The molecular mimicry of these bacterial polySia capsules represents an elegant strategy to evade the host’s immune recognition since they are not considered as foreign. In addition, they confer a physical barrier protecting the pathogen from killing by the complement system PMID: 8884739.

Kinetics and Mechanism

Content is to be added here.

Catalytic Residues

Content is to be added here.

Three-dimensional structures

Content is to be added here.

Family Firsts

First stereochemistry determination

Content is to be added here.

First catalytic nucleophile identification

Content is to be added here.

First general acid/base residue identification

Content is to be added here.

First 3-D structure

Content is to be added here.

References

1. Cantarel BL, Coutinho PM, Rancurel C, Bernard T, Lombard V, and Henrissat B. (2009). The Carbohydrate-Active EnZymes database (CAZy): an expert resource for Glycogenomics. Nucleic Acids Res. 2009;37(Database issue):D233-8. DOI:10.1093/nar/gkn663 |

2. Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. The Biochemist, vol. 30, no. 4., pp. 26-32. Download PDF version.