Zhang Rongguang, Wu Ruiying, Joachimiak Grazyna, Mazmanian Sarkis K, Missiakas Dominique M, Gornicki Piotr, Schneewind Olaf, Joachimiak Andrzej
Structural Biology Center and Midwest Center for Structural Genomics, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439 USA.
Structure. 2004 Jul;12(7):1147-56. doi: 10.1016/j.str.2004.06.001.
Surface proteins attached by sortases to the cell wall envelope of bacterial pathogens play important roles during infection. Sorting and attachment of these proteins is directed by C-terminal signals. Sortase B of S. aureus recognizes a motif NPQTN, cleaves the polypeptide after the Thr residue, and attaches the protein to pentaglycine cross-bridges. Sortase B of B. anthracis is thought to recognize the NPKTG motif, and attaches surface proteins to m-diaminopimelic acid cross-bridges. We have determined crystal structure of sortase B from B. anthracis and S. aureus at 1.6 and 2.0 A resolutions, respectively. These structures show a beta-barrel fold with alpha-helical elements on its outside, a structure thus far exclusive to the sortase family. A putative active site located on the edge of the beta-barrel is comprised of a Cys-His-Asp catalytic triad and presumably faces the bacterial cell surface. A putative binding site for the sorting signal is located nearby.
被分选酶连接到细菌病原体细胞壁包膜上的表面蛋白在感染过程中发挥着重要作用。这些蛋白的分选和连接由C端信号引导。金黄色葡萄球菌的分选酶B识别NPQTN基序，在苏氨酸残基后切割多肽，并将蛋白质连接到五甘氨酸交联桥上。炭疽芽孢杆菌的分选酶B被认为识别NPKTG基序，并将表面蛋白连接到间二氨基庚二酸交联桥上。我们分别以1.6埃和2.0埃的分辨率确定了炭疽芽孢杆菌和金黄色葡萄球菌分选酶B的晶体结构。这些结构显示出一个β桶状折叠，其外部有α螺旋元件，这种结构迄今为止是分选酶家族所独有的。位于β桶边缘的一个假定活性位点由半胱氨酸-组氨酸-天冬氨酸催化三联体组成，大概面向细菌细胞表面。分选信号的一个假定结合位点位于附近。
