Molecular design of fluorescent labeled glycosides as acceptor substrates for sialyltransferases.
A series of dansyl-labeled glycosides with di-, tetra-, and hexasaccharides carrying the terminal N-acetyllactosamine (LacNAc) sequence were synthesized as acceptor substrates for α2,6- and α2,3-sialyltransferases. As an alternative design, dansyl-labeled LacNAc glycoside carrying a long-spacer linked glycan was engineered by replacement of the LacNAc or lactose units with an alkyl chain. In addition, we designed a dansyl-labeled bi-antennary LacNAc glycoside as an N-linked oligosaccharide mimetic, such as asialo-α(1)-acid glycoprotein. The kinetic parameters for the transfer reaction of synthesized dansyl-labeled glycosides by sialyltransferases were determined by the fluorescent HPLC method. The catalytic efficiencies (V(max)/K(m)) of acceptor substrates carrying the terminal LacNAc sequence with various length glycans in the array for α2,6- and α2,3-sialyltransferases decreased in a glycan length-dependent manner. Furthermore, of the acceptor substrates tested, dansyl-labeled bi-antennary LacNAc glycoside displayed the most favorable K(m) value for α2,6- and α2,3-sialyltransferases.
Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, Japan. dmogata@ipc.shizuoka.ac.jp
Makoto
M
Ogata
Takakiyo
T
Obara
Yasushi
Y
Chuma
Takeomi
T
Murata
Enoch Y
EY
Park
Taichi
T
Usui
D000606:Amino Sugars; D003619:Dansyl Compounds; D005456:Fluorescent Dyes / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D009844:Oligosaccharides; D011485:Protein Binding; D012799:Sialyltransferases / Q000378:metabolism*
D000606:Amino Sugars; D003619:Dansyl Compounds; D005456:Fluorescent Dyes; D006027:Glycosides; D009844:Oligosaccharides; C000458:N-acetyllactosamine; D012799:Sialyltransferases