Crystal structure of α/β‐galactoside α2,3‐sialyltransferase from a luminous marine bacterium, Photobacterium phosphoreum

Abstract

Edited by Judit OvádiKeywords: a2,3-SialyltransfeaseCrystal structure JT-ISH-467 Sialic acid Broad substrate specificity Active conformation Photobacterium phosphoreum a b s t r a c t a/b-Galactoside a2,3-sialyltransferase produced by Photobacterium phosphoreum JT-ISH-467 is a unique enzyme that catalyzes the transfer of N-acetylneuraminic acid residue from cytidine monophosphate N-acetylneuraminic acid to acceptor carbohydrate groups. The enzyme recognizes both mono-and di-saccharides as acceptor substrates, and can transfer Neu5Ac to both a-galactoside and b-galactoside, efficiently. To elucidate the structural basis for the broad acceptor substrate specificity, we determined the crystal structure of the a2,3-sialyltransferase in complex with CMP. The overall structure belongs to the glycosyltransferase-B structural group. We could model a reasonable active conformation structure based on the crystal structure. The predicted structure suggested that the broad substrate specificity could be attributed to the wider entrance of the acceptor substrate binding site.

X-ray crystallographic structure of a bacterial polysialyltransferase provides insight into the biosynthesis of capsular polysialic acid

“…2b). All described interactions between Mh PST and cytosine highly resemble the situation observed for Pasteurella multocida mono-sialyltransferase PmST1 and related enzymes of the GT80 family 41–43 .…”

Loss-of-Function Mutation in Bi-Functional Marine Bacterial Sialyltransferase

“…In a previous study, 32) the Phe341, Glu342, and Ser360 amino acid residues of ÁNpp23ST were found to be associated with the donor substrate. Hence we expressed several mutant enzymes that had mutations at the amino acid residues in the donor substrate-binding site of ÁNpp23ST to obtain more information.…”

“…Hitomi KAJIWARA, Present address: Intellectual Property Center, Legal Division, Japan Tobacco Inc., 2-2-1 Toranomon, Minato-ku, Tokyo 105-8422, Japan; Tel: +81-3-5572-3357; Fax: +81-3-5572-1412; E-mail: hitomi.kajiwara@jt.com; Takeshi YAMAMOTO, Present address: Product Science Division, Japan Tobacco Inc., 6-2 Umegaoka, Aoba-ku, Yokohama, Kanagawa 227-8512, Japan; Tel: +81-45-345-5249; Fax: +81-45-973-6781; E-mail: takeshi.yamamoto@jt.com Abbreviations: CMP, cytidine 5 0 -monophosphate; Neu5Ac, N-acetylneuraminic acid; CMP-Neu5Ac, cytidine 5 0 -monophospho-N-acetylneuraminic acid; Gal, galactose; GalNAc, N-acetylgalactosamine; NaCl, sodium chloride; PA, pyridyl amino; HPLC, high-performance liquid chromatography; NMR, nuclear magnetic resonance of 2,3-sialyltransferase (CstI) and 2,3-/2,8-sialyltransferase (CstII) cloned from C. jejuni, 27,28) multifunctional 2,3-sialyltransferase cloned from P. multocida (Á24PmST1), 29,30) 2,6-sialyltransferase cloned from Photobacterium sp. (Á16pspST6), 31) and 2,3-sialyltransferase cloned from P. phosphoreum, 32) a NH 2 -terminal truncated form of which was also reported. Based on these studies, substrate recognition and catalytic mechanisms have been proposed for these enzymes, but to date the roles of the amino acid residues around the catalytic sites of these bacterial sialyltransferases have not been comprehensively studied.…”

PmST3 from Pasteurella multocida encoded by Pm1174 gene is a monofunctional α2–3-sialyltransferase

“…1). In addition to the crystal structure of a porcine ST3Gal-I, a GT29 family mammalian sialyltransferase (Rao et al 2009), structures of several bacterial sialyltransferases from GT42 (Chiu et al 2004(Chiu et al , 2007, GT80 (Ni et al 2006(Ni et al , 2007Kakuta et al 2008;Iwatani et al 2009), and more recently GT52 (Lin et al 2011) glycosyltransferase families have been reported. Unlike sialyltransferases from GT80 (e.g., PmST1, α2-6-sialyltransferase from Photobacterium sp.…”