Structural heterogeneity of carbohydrate modifications affects serospecificity of Campylobacter flagellins
Structural heterogeneity of carbohydrate modifications affects serospecificity of Campylobacter flagellins
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DOI：
10.1046/j.1365-2958.2002.03185.x
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发表时间：
2002-10-01
影响因子：
3.6
通讯作者：
Guerry, P
中科院分区：
文献类型：
--
作者：
Logan, SM;Kelly, JF;Guerry, P
结肠弯曲菌VC167鞭毛蛋白的16个氨基酸残基被伪氨基酸及其相关的三种衍生物翻译后修饰。主要的修饰是5，7-diacetamido-3，5，7，9-tetradeoxy-L-glycero-L-manno-nonulosonic酸(伪氨基酸，Pse5Ac7Ac)，这是先前对来自空肠弯曲菌81-176的鞭毛蛋白的修饰。VC167缺少81-176中存在的两个修饰，而是具有质量431和432 Da的两个独特修饰。空肠弯曲菌81-176和大肠埃希菌VC167的Flagellin也被乙酰氨基形式的伪氨基酸(PseAm)修饰，但串联质谱仪显示两株PseAm的结构不同。在大肠杆菌VC167中合成PseAM至少需要6个PTM基因。相反，PseAm在空肠弯曲菌81-176中是通过使用PSEA基因产物的另一种途径合成的。通过SDS-PAGE凝胶中鞭毛蛋白表观M-r的改变、等电聚焦(IEF)模式的改变以及与抗血清LAH2免疫反应性的丧失，可以检测到大肠杆菌VC167中PTM基因的突变。这些变化对应于鞭毛蛋白315Da和431Da修饰的丢失。将突变的VC167 Ptm与反式81-176的PSEA基因互补后，鞭毛蛋白含有315和431 Da的修饰，但这些鞭毛蛋白对LAH2抗体无反应，表明PseAm基因编码的独特形式的PseAm与鞭毛细丝的血清特异性有关。
Flagellin from Campylobacter coli VC167 is post-translationally modified at 16 amino acid residues with pseudaminic acid and three related derivatives. The predominant modification was 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (pseudaminic acid, Pse5Ac7Ac), a modification that has been described previously on flagellin from Campylobacter jejuni 81-176. VC167 lacked two modifications present in 81-176 and instead had two unique modifications of masses 431 and 432 Da. Flagellins from both C. jejuni 81-176 and C. coli VC167 were also modified with an acetamidino form of pseudaminic acid (PseAm), but tandem mass spectrometry indicated that the structure of PseAm differed in the two strains. Synthesis of PseAm in C. coli VC167 requires a minimum of six ptm genes. In contrast, PseAm is synthesized in C. jejuni 81-176 via an alternative pathway using the product of the pseA gene. Mutation of the ptm genes in C. coli VC167 can be detected by changes in apparent M-r of flagellin in SDS-PAGE gels, changes in isoelectric focusing (IEF) patterns and loss of immunoreactivity with antiserum LAH2. These changes corresponded to loss of both 315 Da and 431 Da modifications from flagellin. Complementation of the VC167 ptm mutants with the 81-176 pseA gene in trans resulted in flagellins containing both 315 and 431 Da modifications, but these flagellins remained unreactive in LAH2 antibody, suggesting that the unique form of PseAm encoded by the ptm genes contributes to the serospecificity of the flagellar filament.