Geerds Christina, Wohlmann Jens, Haas Albert, Niemann Hartmut H
Department of Chemistry, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld, Germany.
Institute for Cell Biology, University of Bonn, Ulrich-Haberland Strasse 61a, 53121 Bonn, Germany.
Acta Crystallogr F Struct Biol Commun. 2014 Jul;70(Pt 7):866-71. doi: 10.1107/S2053230X14009911. Epub 2014 Jun 18.
Members of the virulence-associated protein (Vap) family from the pathogen Rhodococcus equi regulate virulence in an unknown manner. They do not share recognizable sequence homology with any protein of known structure. VapB and VapA are normally associated with isolates from pigs and horses, respectively. To contribute to a molecular understanding of Vap function, the crystal structure of a protease-resistant VapB fragment was determined at 1.4 Å resolution. The structure was solved by SAD phasing employing the anomalous signal of one endogenous S atom and two bound Co ions with low occupancy. VapB is an eight-stranded antiparallel β-barrel with a single helix. Structural similarity to avidins suggests a potential binding function. Unlike other eight- or ten-stranded β-barrels found in avidins, bacterial outer membrane proteins, fatty-acid-binding proteins and lysozyme inhibitors, Vaps do not have a next-neighbour arrangement but consist of two Greek-key motifs with strand order 41238567, suggesting an unusual or even unique topology.
来自马红球菌病原体的毒力相关蛋白（Vap）家族成员以未知方式调节毒力。它们与任何已知结构的蛋白质都没有可识别的序列同源性。VapB和VapA通常分别与来自猪和马的分离株相关。为了从分子层面理解Vap的功能，以1.4Å分辨率确定了一种抗蛋白酶VapB片段的晶体结构。该结构通过利用一个内源性S原子和两个低占有率结合Co离子的异常信号的SAD相位法解析。VapB是一个具有单螺旋的八链反平行β桶。与抗生物素蛋白的结构相似性表明其具有潜在的结合功能。与在抗生物素蛋白、细菌外膜蛋白、脂肪酸结合蛋白和溶菌酶抑制剂中发现的其他八链或十链β桶不同，Vap没有相邻排列，而是由两个希腊钥匙基序组成，链序为41238567，这表明其拓扑结构不同寻常甚至独特。
