期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 283, 期 21, 页码 14327-14334出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M708927200
关键词
-
资金
- NIGMS NIH HHS [R01 GM 071007, F32 GM072341, R01 GM071007, F32 GM 072341] Funding Source: Medline
The opportunistic yeast Cryptococcus neoformans causes serious disease in humans and expresses a prominent polysaccharide capsule that is required for its virulence. Little is known about how this capsule is synthesized. We previously identified a beta 1,2-xylosyltransferase (Cxt1p) with in vitro enzymatic activity appropriate for involvement in capsule synthesis. Here, we investigate C. neoformans strains in which the corresponding gene has been deleted (cxt1 Delta). Loss of CXT1 does not affect in vitro growth of the mutant cells or the general morphology of their capsules. However, NMR structural analysis of the two main capsule polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), showed that both were missing beta 1,2-xylose residues. There was an similar to 30% reduction in the abundance of this residue in GXM in mutant compared with wild-type strains, and mutant GalXM was almost completely devoid of beta 1,2-linked xylose. The GalXM from the mutant strain was also missing a beta 1,3- linked xylose residue. Furthermore, deletion of CXT1 led to attenuation of cryptococcal growth in a mouse model of infection, suggesting that the affected xylose residues are important for normal host-pathogen interactions. Cxt1p is the first glycosyltransferase with a defined role in C. neoformans capsule biosynthesis, and cxt1 Delta is the only strain identified to date with structural alterations of the capsule polysaccharide GalXM.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据