Mesnage S, Fontaine T, Mignot T, Delepierre M, Mock M, Fouet A
Toxines et Pathogénie Bactériennes (URA 1858, CNRS), Institut Pasteur, 28 rue du Dr Roux, 75724 Paris, cédex 15, France.
EMBO J. 2000 Sep 1;19(17):4473-84. doi: 10.1093/emboj/19.17.4473.
Several bacterial proteins are non-covalently anchored to the cell surface via an S-layer homology (SLH) domain. Previous studies have suggested that this cell surface display mechanism involves a non-covalent interaction between the SLH domain and peptidoglycan-associated polymers. Here we report the characterization of a two-gene operon, csaAB, for cell surface anchoring, in Bacillus anthracis. Its distal open reading frame (csaB) is required for the retention of SLH-containing proteins on the cell wall. Biochemical analysis of cell wall components showed that CsaB was involved in the addition of a pyruvyl group to a peptidoglycan-associated polysaccharide fraction, and that this modification was necessary for binding of the SLH domain. The csaAB operon is present in several bacterial species that synthesize SLH-containing proteins. This observation and the presence of pyruvate in the cell wall of the corresponding bacteria suggest that the mechanism described in this study is widespread among bacteria.
几种细菌蛋白通过S层同源性（SLH）结构域非共价锚定在细胞表面。先前的研究表明，这种细胞表面展示机制涉及SLH结构域与肽聚糖相关聚合物之间的非共价相互作用。在此，我们报告了炭疽芽孢杆菌中一个用于细胞表面锚定的双基因操纵子csaAB的特性。其远端开放阅读框（csaB）是含SLH蛋白保留在细胞壁上所必需的。对细胞壁成分的生化分析表明，CsaB参与了将一个丙酮酸基团添加到肽聚糖相关多糖组分的过程，并且这种修饰对于SLH结构域的结合是必需的。csaAB操纵子存在于几种合成含SLH蛋白的细菌物种中。这一观察结果以及相应细菌细胞壁中丙酮酸的存在表明，本研究中描述的机制在细菌中广泛存在。
