Crystal structures of sialyltransferase from Photobacterium damselae.

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 ?2-6-sialyltransferase has been used efficiently in enzymatic and chemoenzymatic synthesis of ?2-6-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.

SUBMITTER: Huynh N 

PROVIDER: S-EPMC4268365 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature