Antimicrobial peptide resistance of Vibrio cholerae results from an LPS modification pathway related to nonribosomal peptide synthetases.
Antimicrobial peptide resistance of Vibrio cholerae results from an LPS modification pathway related to nonribosomal peptide synthetases.
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DOI：
10.1021/cb500438x
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发表时间：
2014-10-17
影响因子：
4
通讯作者：
Trent MS
中科院分区：
文献类型：
--
作者：
Henderson JC;Fage CD;Cannon JR;Brodbelt JS;Keatinge-Clay AT;Trent MS
当前流行的01型霍乱弧菌El - Tor生物型对多粘菌素具有耐药性，而以前流行的经典生物型菌株对多粘菌素敏感。在霍乱杆菌中发现的almEFG操纵子通过脂多糖的糖基化对多粘菌素具有100倍的抗性。在这里，我们提出了AlmEFG途径初始步骤的机制确定。我们证实AlmF是一种氨基酰基载体蛋白，并确定AlmE是激活AlmF作为功能性载体蛋白所需的酶。结合结构信息和活性分析，鉴定了一对对介导AlmE甘氨酸特异性很重要的活性位点残基。综上所述，AlmE及其甘酰基腺苷酸中间体复合物的结构揭示了AlmE与革兰氏阳性d-丙氨酸/d-丙烯酰载体蛋白连接酶有关，而AlmEFG系统中的三种蛋白质形成了类似于非核糖体肽合成酶分工的化学途径。
The current pandemic El Tor biotype of O1 Vibrio cholerae is resistant to polymyxins, whereas the previous pandemic strain of the classical biotype is polymyxin sensitive. The almEFG operon found in El Tor V. cholerae confers >100-fold resistance to polymyxins through the glycylation of lipopolysaccharide. Here, we present the mechanistic determination of initial steps in the AlmEFG pathway. We verify that AlmF is an aminoacyl carrier protein and identify AlmE as the enzyme required to activate AlmF as a functional carrier protein. A combination of structural information and activity assays was used to identify a pair of active site residues that are important for mediating AlmE glycine specificity. Overall, the structure of AlmE in complex with its glycyl-adenylate intermediate reveals that AlmE is related to Gram-positive d-alanine/d-alanyl carrier protein ligase, while the trio of proteins in the AlmEFG system forms a chemical pathway that resembles the division of labor in nonribosomal peptide synthetases.