Glycosylation of Campylobacter flagella

弯曲杆菌鞭毛的糖基化

• 批准号: 6707508
• 负责人: Patricia Guerry
• 金额: $ 23.46万
• 依托单位: HENRY M. JACKSON FDN FOR THE ADV MIL/MED
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6707508
• 关键词: Campylobacter; bacteria infection mechanism; carbohydrate biosynthesis; cilium /flagellum motility; clinical research; ferrets; flagellin; flagellum; gene expression; gene mutation; genetic strain; genetic transcription; glycosylation; laboratory rabbit; polymerase chain reaction; posttranslational modifications; protein structure; site directed mutagenesis; surface antigens; virulence

DESCRIPTION (provided by applicant): Campylobacter jejuni is the leading cause of foodborne illness in North America and is among the major causes of bacterial diarrhea worldwide. Flagella and motility are required for intestinal colonization and invasion of intestinal epithelial cells by C. jejuni, and flagellin is an immunodominant and possibly a protective antigen. Flagellin from C. jejuni strain 81-176 and Campylobacter coli strain VC167 are glycosylated at 19 and 16 serine or threonine residues, respectively, with a 9 carbon sugar called pseudaminic acid and derivatives of pseudaminic acid. The modifications, which account for approximately 10% of the weight of these glycoproteins, are surface exposed on the flagella filament and are likely involved in interaction of flagellin with the eukaryotic host. Genetic analyses indicate that the pathway for biosynthesis of pseudaminic acid is conserved in both 81-176 and VC167. Flagellins from both strains contain minor modifications that are acetamidino forms of pseudaminic acid (mass 315 Da). However, the 315 Da group synthesized by 81-176 and VC 167 are structurally and immunologically distinct and are synthesized by independent pathways in each organism. The data suggest that campylobacter flagellin needs to be glycosylated in order to be exported and/or assembled into a filament. A mutant in 81-176 that is unable to synthesize the acetamidino form of pseudaminic acid appears to be attenuated in virulence. The aim of this study is to further elucidate the pathways by which the different forms of pseudaminic acid are synthesized and to study unique aspects of the regulation of these glycosylation genes. Site-specific mutagenesis will be done on flagellin to eliminate modification sites sequentially in order to determine sites that are critical for flagella function and the rules of site occupancy. The biological role of flagella glycosylation will be studied by examining a series of mutants in in vitro and in vivo assays of virulence.

描述（由申请方提供）：空肠弯曲菌是北美食源性疾病的主要原因，也是全球细菌性腹泻的主要原因之一。 鞭毛和运动是C.鞭毛蛋白是一种免疫显性抗原，可能是一种保护性抗原。 鞭毛蛋白C.空肠杆菌菌株81-176和结肠弯曲杆菌菌株VC 167分别在19和16个丝氨酸或苏氨酸残基处被称为假氨基酸和假氨基酸衍生物的9碳糖糖基化。 这些修饰约占这些糖蛋白重量的10%，暴露在鞭毛丝的表面，并且可能参与鞭毛蛋白与真核宿主的相互作用。 遗传分析表明，假氨基酸的生物合成途径在81-176和VC 167中是保守的。 来自两种菌株的鞭毛蛋白都含有少量修饰，即假氨基酸的乙脒基形式（质量315 Da）。 然而，由81-176和VC 167合成的315 Da基团在结构上和免疫学上是不同的，并且在每个生物体中通过独立的途径合成。 数据表明，弯曲杆菌鞭毛蛋白需要糖基化，以便输出和/或组装成细丝。 81-176中不能合成乙脒基形式的假氨基酸的突变体似乎在毒力上减弱。 本研究的目的是进一步阐明不同形式的假氨基酸的合成途径，并研究这些糖基化基因的调控的独特方面。 将对鞭毛蛋白进行位点特异性诱变以依次消除修饰位点，以确定对鞭毛功能至关重要的位点和位点占据规则。 鞭毛糖基化的生物学作用将通过在体外和体内毒力测定中检查一系列突变体来研究。