Crystal structures of sialyltransferase from Photobacterium damselae.

Nhung Huynh, Yanhong Li, Hai Yu, Shengshu Huang, Kam Lau, Xi Chen, Andrew J Fisher

Index: FEBS Lett. 588(24) , 4720-9, (2014)

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Abstract

Sialyltransferase structures fall into either GT-A or GT-B glycosyltransferase fold. Some sialyltransferases from the Photobacterium genus have been shown to contain an additional N-terminal immunoglobulin (Ig)-like domain. Photobacterium damselae α2-6-sialyltransferase has been used efficiently in enzymatic and chemoenzymatic synthesis of α2-6-linked sialosides. Here we report three crystal structures of this enzyme. Two structures with and without a donor substrate analog CMP-3F(a)Neu5Ac contain an immunoglobulin (Ig)-like domain and adopt the GT-B sialyltransferase fold. The binary structure reveals a non-productive pre-Michaelis complex, which are caused by crystal lattice contacts that prevent the large conformational changes. The third structure lacks the Ig-domain. Comparison of the three structures reveals small inherent flexibility between the two Rossmann-like domains of the GT-B fold. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.