Biosynthesis of a conserved glycolipid anchor for Gram-negative bacterial capsules
Biosynthesis of a conserved glycolipid anchor for Gram-negative bacterial capsules
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DOI：
10.1038/s41589-019-0276-8
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发表时间：
2019-06-01
影响因子：
14.8
通讯作者：
Whitfield, Chris
中科院分区：
文献类型：
--
作者：
Doyle, Liam;Ovchinnikova, Olga G.;Whitfield, Chris
Several important Gram-negative bacterial pathogens possess surface capsular layers composed of hypervariable long-chain polysaccharides linked via a conserved 3-deoxy-beta-D-manno-oct-2-ulosonic acid (beta-Kdo) oligosaccharide to a phosphatidylglycerol residue. The pathway for synthesis of the terminal glycolipid was elucidated by determining the structures of reaction intermediates. In Escherichia coli, KpsS transfers a single Kdo residue to phosphatidylglycerol; this primer is extended using a single enzyme (KpsC), possessing two cytidine 5'-monophosphate (CMP)-Kdo-dependent glycosyltransferase catalytic centers with different linkage specificities. The structure of the N-terminal beta-(2 -> 4) Kdo transferase from KpsC reveals two alpha/beta domains, supplemented by several helices. The N-terminal Rossmann-like domain, typically responsible for acceptor binding, is severely reduced in size compared with canonical GT-B folds in glycosyltransferases. The similar structure of the C-terminal beta-(2 -> 7) Kdo transferase indicates a past gene duplication event. Both Kdo transferases have a narrow active site tunnel, lined with key residues shared with GT99 beta-Kdo transferases. This enzyme provides the prototype for the GT107 family.
