Navarre W W, Ton-That H, Faull K F, Schneewind O
Department of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, California 90095, USA.
J Biol Chem. 1998 Oct 30;273(44):29135-42. doi: 10.1074/jbc.273.44.29135.
Surface proteins of the Gram-positive organism Staphylococcus aureus are anchored to the bacterial cell wall by a transpeptidation mechanism during which the polypeptide is cleaved between the threonine (T) and the glycine (G) of the LPXTG motif. The carboxyl of threonine is subsequently amide linked to the amino of the pentaglycyl cross-bridge within the staphylococcal peptidoglycan. Previous work examined the anchor structure of surface proteins solubilized from the peptidoglycan by treatment with lysostaphin or phi11 hydrolase and identified COOH-terminally linked triglycyl or L-Ala-D-iGln-L-Lys(Gly5)-D-Ala and MurNAc-L-Ala-D-iGln-L-Lys(Gly5)-D-Ala-GlcNAc, respectively. Here, we report the anchor structure of surface proteins solubilized with N-acetylmuramidase and N-acetylmuramyl-L-alanine amidase. N-Acetylmuramidase-released surface protein was linked to MurNAc-L-Ala-D-iGln-L-Lys(Gly5)-D-Ala-GlcNAc, whereas N-acetylmuramyl-L-alanine amidase treatment of the cell wall solubilized surface proteins linked to L-Ala-D-iGln-L-Lys(Gly5)-D-Ala. Most, but not all, anchor structures were cross-linked to other cell wall subunits, in which the D-alanyl at position four was amide linked to the pentaglycyl of a neighboring wall peptide.
革兰氏阳性菌金黄色葡萄球菌的表面蛋白通过转肽作用机制锚定在细菌细胞壁上，在此过程中，多肽在LPXTG基序的苏氨酸（T）和甘氨酸（G）之间被切割。随后，苏氨酸的羧基与葡萄球菌肽聚糖内五肽甘氨酸交联桥的氨基形成酰胺键。此前的研究通过用溶葡萄球菌素或phi11水解酶处理从肽聚糖中溶解的表面蛋白，研究了其锚定结构，并分别鉴定出COOH末端连接的三肽甘氨酰或L-Ala-D-iGln-L-Lys(Gly5)-D-Ala以及MurNAc-L-Ala-D-iGln-L-Lys(Gly5)-D-Ala-GlcNAc。在此，我们报告了用N-乙酰胞壁酸酶和N-乙酰胞壁酰-L-丙氨酸酰胺酶溶解的表面蛋白的锚定结构。N-乙酰胞壁酸酶释放的表面蛋白与MurNAc-L-Ala-D-iGln-L-Lys(Gly5)-D-Ala-GlcNAc相连，而用N-乙酰胞壁酰-L-丙氨酸酰胺酶处理细胞壁可溶解与L-Ala-D-iGln-L-Lys(Gly5)-D-Ala相连的表面蛋白。大多数（但不是全部）锚定结构与其他细胞壁亚基交联，其中第4位的D-丙氨酰通过酰胺键与相邻壁肽的五肽甘氨酰相连。
