title: Trans-sialidase activity of Photobacterium damsela alpha2,6-sialyltransferase and its application in the synthesis of sialosides.
abstract: Trans-sialidases catalyze the transfer of a sialic acid from one sialoside to an acceptor to form a new sialoside. alpha2,3-Trans-sialidase activity was initially discovered in the parasitic protozoan Trypanosoma cruzi, and more recently was found in a multifunctional Pasteurella multocida sialyltransferase PmST1. alpha2,8-Trans-sialidase activity was also described for a multifunctional Campylobacter jejuni sialyltransferase CstII. We report here the discovery of the alpha2,6-trans-sialidase activity of a previously reported recombinant truncated bacterial alpha2,6-sialyltransferase from Photobacterium damsela (Delta15Pd2,6ST). This is the first time that the alpha2,6-trans-sialidase activity has ever been identified. Kinetic studies indicate that Delta15Pd2,6ST-catalyzed trans-sialidase reaction follows a ping-pong bi-bi reaction mechanism. Cytidine 5'-monophosphate, the product of sialyltransferase reactions, is not required by the trans-sialidase activity of the enzyme but enhances the trans-sialidase activity modestly as a non-essential activator. Using chemically synthesized Neu5AcalphapNP and LacbetaMU, alpha2,6-linked sialoside Neu5Acalpha2,6LacbetaMU has been obtained in one-step in high yield using the trans-sialidase activity of Delta15Pd2,6ST. In addition to the alpha2,6-trans-sialidase activity, Delta15Pd2,6ST also has alpha2,6-sialidase activity. The multifunctionality is thus a common feature of many bacterial sialyltransferases.
authors.affiliation: Department of Chemistry, University of California, Davis, CA 95616, USA.
authors.forename: Jiansong
authors.initials: J
authors.lastname: Cheng
authors.forename: Shengshu
authors.initials: S
authors.lastname: Huang
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Li
authors.forename: Kam
authors.initials: K
authors.lastname: Lau
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
mesh_terms: D002384:Catalysis; D004789:Enzyme Activation; D006023:Glycoproteins / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid / Q000096:biosynthesis* / Q000737:chemistry; D009439:Neuraminidase / Q000378:metabolism*; D010776:Photobacterium / Q000201:enzymology*; D012799:Sialyltransferases / Q000378:metabolism*; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase
chemical_list: D006023:Glycoproteins; D012799:Sialyltransferases; C069715:trans-sialidase; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase