N-Glycosylation of Campylobacter jejuni Surface Proteins Promotes Bacterial Fitness
N-Glycosylation of Campylobacter jejuni Surface Proteins Promotes Bacterial Fitness
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DOI：
10.1128/iai.01370-12
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发表时间：
2013-05-01
影响因子：
3.1
通讯作者：
Szymanski, Christine M.
中科院分区：
文献类型：
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作者：
Alemka, Abofu;Nothaft, Harald;Szymanski, Christine M.
空肠弯曲菌是世界范围内引起人类细菌性胃肠炎的病原体。相比之下，尽管大量殖民，C。空肠在鸡体内保持着一种消化方式。食用受污染的鸡肉制品被认为是C.空肠传染给人类。C.空肠具有N-连接蛋白糖基化系统，该系统已被充分表征并修饰了60多种周质和膜结合蛋白。然而，这种修饰在C.空肠尚未探查。我们假设N-聚糖保护C。空肠表面蛋白的作用。梭与野生型（WT）细胞相比，表达寡糖基转移酶缺陷的空肠pglB突变体在补充有鸡盲肠内容物（CCC）的培养基中表现出降低的生长。通过热处理或用蛋白酶抑制剂灭活盲肠蛋白酶完全恢复细菌活力并部分挽救细菌生长。生理浓度的胰蛋白酶，但不糜蛋白酶，也减少C。空肠pglB突变体CFU。活或死染色表明CCC优先影响C.空肠生长与细菌活力相反。我们确定了多种鸡盲肠蛋白酶的质量指纹图谱。靶向特定类别的蛋白酶抑制剂的使用表明，金属蛋白酶和丝氨酸蛋白酶都参与寡糖基转移酶突变体的衰减生长。总之，蛋白质N-连接的表面蛋白的糖基化可以增强C。通过保护细菌蛋白质免受肠道蛋白酶的切割，
Campylobacter jejuni is the etiologic agent of human bacterial gastroenteritis worldwide. In contrast, despite heavy colonization, C. jejuni maintains a commensal mode of existence in chickens. The consumption of contaminated chicken products is thought to be the principal mode of C. jejuni transmission to the human population. C. jejuni harbors a system for N-linked protein glycosylation that has been well characterized and modifies more than 60 periplasmic and membrane-bound proteins. However, the precise role of this modification in the biology of C. jejuni remains unexplored. We hypothesized that the N-glycans protect C. jejuni surface proteins from the action of gut proteases. The C. jejuni pglB mutant, deficient in the expression of the oligosaccharyltransferase, exhibited reduced growth in medium supplemented with chicken cecal contents (CCC) compared with that of wild-type (WT) cells. Inactivation of the cecal proteases by heat treatment or with protease inhibitors completely restored bacterial viability and partially rescued bacterial growth. Physiological concentrations of trypsin, but not chymotrypsin, also reduced C. jejuni pglB mutant CFU. Live or dead staining indicated that CCC preferentially influenced C. jejuni growth as opposed to bacterial viability. We identified multiple chicken cecal proteases by mass fingerprinting. The use of protease inhibitors that target specific classes indicated that both metalloproteases and serine proteases were involved in the attenuated growth of the oligosaccharyltransferase mutant. In conclusion, protein N-linked glycosylation of surface proteins may enhance C. jejuni fitness by protecting bacterial proteins from cleavage due to gut proteases.