Sortase D Forms the Covalent Bond That Links BcpB to the Tip of Bacillus cereus Pili
Sortase D Forms the Covalent Bond That Links BcpB to the Tip of Bacillus cereus Pili
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DOI：
10.1074/jbc.m900927200
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发表时间：
2009-05-08
影响因子：
4.8
通讯作者：
Schneewind, Olaf
中科院分区：
文献类型：
--
作者：
Budzik, Jonathan M.;Oh, So-Young;Schneewind, Olaf
蜡状芽孢杆菌和其他革兰氏阳性细菌通过分选酶D催化的转肽机制从主要和次要菌毛蛋白前体底物加工皮利。在切割主要菌毛蛋白BcpA的LPXTG分选信号后，分选酶D在另一个BcpA亚基的YPKN基序内的C-末端苏氨酸和赖氨酸的氨基之间形成酰胺键。菌毛装配在分选酶A切割BcpA分选信号后终止，导致BcpA和细胞壁交叉桥之间的共价键。在这里，我们表明，BcpB的IPNTG分选信号，次要菌毛蛋白，被分选酶D切割，但不被分选酶A切割。BcpB的C末端苏氨酸与BcpA的YPKN基序酰胺连接，从而将BcpB定位在皮利的尖端。因此，次要菌毛蛋白的分选信号的独特属性为革兰氏阳性细菌提供了皮利的通用机制排序组装。
Bacillus cereus and other Gram-positive bacteria elaborate pili via a sortase D-catalyzed transpeptidation mechanism from major and minor pilin precursor substrates. After cleavage of the LPXTG sorting signal of the major pilin, BcpA, sortase D forms an amide bond between the C-terminal threonine and the amino group of lysine within the YPKN motif of another BcpA subunit. Pilus assembly terminates upon sortase A cleavage of the BcpA sorting signal, resulting in a covalent bond between BcpA and the cell wall cross-bridge. Here, we show that the IPNTG sorting signal of BcpB, the minor pilin, is cleaved by sortase D but not by sortase A. The C-terminal threonine of BcpB is amide-linked to the YPKN motif of BcpA, thereby positioning BcpB at the tip of pili. Thus, unique attributes of the sorting signals of minor pilins provide Gram-positive bacteria with a universal mechanism ordering assembly of pili.