Functional analysis of the Campylobacter jejuni N-linked protein glycosylation pathway
Functional analysis of the Campylobacter jejuni N-linked protein glycosylation pathway
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DOI：
10.1111/j.1365-2958.2005.04519.x
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发表时间：
2005-03-01
影响因子：
3.6
通讯作者：
Wren, BW
中科院分区：
文献类型：
--
作者：
Linton, D;Dorrell, N;Wren, BW
在这份报告中，我们描述了最近发现的N-连接的糖基化位点的人类细菌病原体空肠弯曲菌，第一个这样的系统中发现的一个物种从域细菌的表征。我们利用该位点在大肠杆菌中发挥作用的能力，通过突变和结构分析证明，变体聚糖结构可以转移到蛋白质上，表明假定的寡糖基转移酶PgIB的特异性放松。来自这些变异聚糖的结构数据使我们能够推断出五个单独的糖基转移酶在N-连接七糖的生物合成中的作用。此外，我们还证明了C. jejuni和E.大肠杆菌来源的途径可以在N-连接的糖蛋白的生物合成中相互作用。特别是E.大肠杆菌编码的WecA蛋白是一种参与糖脂生物合成的UDP-GlcNAc：十一异戊二烯磷酸GlcNAc-1-磷酸转移酶，它提供了一种替代的N-连接七糖生物合成途径，绕过了对C.空肠衍生糖基转移酶PgIC。这是第一个实验证据表明，N-连接聚糖的生物合成发生在转移到蛋白质之前的脂质连接前体上。这些发现为理解细菌中N-连接蛋白糖基化的过程和设计利用该系统进行糖工程的策略提供了框架。
We describe in this report the characterization of the recently discovered N-linked glycosylation locus of the human bacterial pathogen Campylobacter jejuni, the first such system found in a species from the domain Bacteria. We exploited the ability of this locus to function in Escherichia coli to demonstrate through mutational and structural analyses that variant glycan structures can be transferred onto protein indicating the relaxed specificity of the putative oligosaccharyltransferase PgIB. Structural data derived from these variant glycans allowed us to infer the role of five individual glycosyltransferases in the biosynthesis of the N-linked heptasaccharide. Furthermore, we show that C. jejuni- and E. coli-derived pathways can interact in the biosynthesis of N-linked glycoproteins. In particular, the E. coli encoded WecA protein, a UDP-GlcNAc: undecaprenylphosphate GlcNAc-1-phosphate transferase involved in glycolipid biosynthesis, provides for an alternative N-linked heptasaccharide biosynthetic pathway bypassing the requirement for the C. jejuni-derived glycosyltransferase PgIC. This is the first experimental evidence that biosynthesis of the N-linked glycan occurs on a lipid-linked precursor prior to transfer onto protein. These findings provide a framework for understanding the process of N-linked protein glycosylation in Bacteria and for devising strategies to exploit this system for glycoengineering.