Differential biosynthesis of polysialic acid on neural cell adhesion molecule (NCAM) and oligosaccharide accepters by three distinct α2,8-sialyltransferases, ST8Sia IV (PST), ST8Sia II (STX), and ST8Sia III

被引:92
作者
Angata, K [1 ]
Suzuki, M [1 ]
McAuliffe, J [1 ]
Ding, YL [1 ]
Hindsgaul, O [1 ]
Fukuda, M [1 ]
机构
[1] Burnham Inst, Ctr Canc Res, Glycobiol Program, La Jolla, CA 92037 USA
关键词
D O I
10.1074/jbc.M910204199
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Polysialylated neural cell adhesion molecule (NCAM) is thought to play a critical role in neural development. Polysialylation of NCAM was shown to be achieved by two alpha 2,8-polysialyltransferases, ST8Sia TV (PST) and ST8Sia II (STX), which are moderately related to another alpha 2,8-sialyltransferase, ST8Sia III. Here we describe that all three alpha 2,8-sialyltransferases can utilize oligosaccharides as accepters but differ in the efficiency of adding polysialic acid on NCAM. First, we found that ST8Sia III can form polysialic acid on the enzyme itself (autopolysialylation) but not on NCAM. These discoveries prompted us to determine if ST8Sia IV and ST8Sia II share the property of ST8Sia III in utilizing low molecular weight oligosaccharides as accepters. By using a newly established method, we found that ST8Sia IV, ST8Sia II, and ST8Sia III all add oligosialic and polysialic acid on various sialylated N-acetyllactosaminyl oligosaccharides, including NCAM N-glycans, fetuin N-glycans, synthetic sialylated N-acetyllactosamines, and on a,alpha(2)-HS-glycoprotein, Our results also showed that monosialyl and disialyl N-acetyllactosamines can serve equally as an acceptor, suggesting that no initial addition of alpha 2,8-sialic acid is necessary for the action of polysialyltransferases. Polysialylation of NCAM by ST8Sia IV and ST8Sia II is much more efficient than polysialylation of N-glycans isolated from NCAM. Moreover, ST8Sia. IV and ST8Sia II catalyze polysialylation of NCAM much more efficiently than ST8Sia III. These results suggest that no specific acceptor recognition is involved in polysialylation of low molecular weight sialylated oligosaccharides, whereas the enzymes exhibit pronounced acceptor specificities if glycoproteins are used as accepters.
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页码:18594 / 18601
页数:8
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