title: 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 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.
authors.affiliation: Cell Biology Graduate Program, University of California, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Nhung
authors.initials: N
authors.lastname: Huynh
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Shengshu
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
authors.forename: Kam
authors.initials: K
authors.lastname: Lau
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA. Electronic address: xiichen@ucdavis.edu.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA; Department of Molecular and Cellular Biology, University of California, One Shields Avenue, Davis, CA 95616, USA. Electronic address: ajfisher@ucdavis.edu.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Fisher
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D010776:Photobacterium / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D012799:Sialyltransferases / Q000737:chemistry* / Q000378:metabolism; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
chemical_list: D008670:Metals; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid; D012799:Sialyltransferases; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
keywords: CMP-3F(a)Neu5Ac; Photobacterium damselae; Protein crystal structure; Sialic acid; α2–6-Sialyltransferase