Glycosylation of the self-recognizing Escherichia coli Ag43 autotransporter protein
Glycosylation of the self-recognizing Escherichia coli Ag43 autotransporter protein
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DOI：
10.1128/jb.188.5.1798-1807.2006
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发表时间：
2006-03-01
影响因子：
3.2
通讯作者：
Klemm, P
中科院分区：
文献类型：
--
作者：
Sherlock, O;Dobrindt, U;Klemm, P
糖基化是真核生物中蛋白质功能的一种常见调节，具有重要的生物学意义。然而，在细菌中，蛋白质糖基化是罕见的，并且已知的细菌糖蛋白相对较少。在大肠杆菌中，迄今为止仅描述了两种糖蛋白。在这里，我们介绍了一个新的成员，这个排他性的组，即抗原43（Ag 43），自我识别的自转运蛋白。通过质谱分析，Ag 43被证明是通过在乘客结构域中的几个位置添加庚糖残基而糖基化的。在实验室菌株中观察到通过Aah和TibC糖基转移酶的作用的Ag 43的糖基化。重要的是，还发现Ag 43在野生型菌株中被糖基化，这表明Ag 43-糖基化可能是一种普遍现象。Ag 43的糖基化似乎不干扰其自缔合性质。然而，Ag 43的糖基化形式增强细菌与人细胞系的结合，而Ag 43的非糖基化形式不赋予这种性质。
Glycosylation is a common modulation of protein function in eukaryotes and is biologically important. However, in bacteria protein glycosylation is rare, and relatively few bacterial glycoproteins are known. In Escherichia coli only two glycoproteins have been described to date. Here we introduce a novel member to this exclusive group, namely, antigen 43 (Ag43), a self-recognizing autotransporter protein. By mass spectrometry Ag43 was demonstrated to be glycosylated by addition of heptose residues at several positions in the passenger domain. Glycosylation of Ag43 by the action of the Aah and TibC glycosyltransferases was observed in laboratory strains. Importantly, Ag43 was also found to be glycosylated in a wild-type strain, suggesting that Ag43-glycosylation may be a widespread phenomenon. Glycosylation of Ag43 does not seem to interfere with its self-associating properties. However, the glycosylated form of Ag43 enhances bacterial binding to human cell lines, whereas the nonglycosylated version of Ag43 does not to confer this property.