Kikuchi Yuki, Matsunami Hideyuki, Yamane Midori, Imada Katsumi, Namba Keiichi
Graduate School of Frontier Biosciences, Osaka University, Japan.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Jan 1;65(Pt 1):17-20. doi: 10.1107/S1744309108038207. Epub 2008 Dec 25.
The formation of the bacterial flagellar axial structure, including the filament, the hook and the rod, requires the attachment of a cap complex to the distal end of the growing structure. Because the rod penetrates the peptidoglycan (PG) layer, the rod cap complex is thought to have PG-hydrolyzing activity. FlgJ is a putative rod cap protein whose C-terminal region shows sequence similarity to known muramidases. In this study, FlgJ(120-316), a C-terminal fragment of FlgJ which contains the muramidase region, was overproduced, purified and crystallized. Crystals were obtained by the sitting-drop vapour-diffusion technique using PEG 3350 as a crystallizing agent and belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 38.8, b = 43.9, c = 108.5 A. Anomalous difference Patterson maps calculated from the diffraction data set of a selenomethionine-labelled crystal showed significant peaks in the Harker sections, indicating that the data were suitable for structure determination.
细菌鞭毛轴向结构（包括鞭毛丝、钩形鞘和杆状部）的形成需要一种帽复合体附着在生长结构的远端。由于杆状部穿透肽聚糖（PG）层，因此杆帽复合体被认为具有PG水解活性。FlgJ是一种假定的杆帽蛋白，其C端区域与已知的胞壁质酶具有序列相似性。在本研究中，FlgJ的C端片段FlgJ(120 - 316)（包含胞壁质酶区域）被过量表达、纯化并结晶。通过坐滴气相扩散技术，以聚乙二醇3350作为结晶剂获得了晶体，其属于正交晶系空间群P2(1)2(1)2(1)，晶胞参数a = 38.8、b = 43.9、c = 108.5 Å。从硒代甲硫氨酸标记晶体的衍射数据集计算得到的反常差值帕特森图在哈克截面显示出明显的峰，表明该数据适合用于结构测定。
