Vetting Matthew W, Hegde Subray S, Zhang Yong, Blanchard John S
Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Mar 1;67(Pt 3):296-302. doi: 10.1107/S1744309110053315. Epub 2011 Feb 18.
The protein AlbG is a self-resistance factor against albicidin, a nonribosomally encoded hybrid polyketide-peptide with antibiotic and phytotoxic properties produced by Xanthomonas albilineans. Primary-sequence analysis indicates that AlbG is a member of the pentapeptide-repeat family of proteins (PRP). The structure of AlbG from X. albilineans was determined at 2.0 Å resolution by SAD phasing using data collected from a single trimethyllead acetate derivative on a home source. AlbG folds into a right-handed quadrilateral β-helix composed of approximately eight semi-regular coils. The regularity of the β-helix is blemished by a large loop/deviation in the β-helix between coils 4 and 5. The C-terminus of the β-helix is capped by a dimerization module, yielding a dimer with a 110 Å semi-collinear β-helical axis. This method of dimer formation appears to be common to all PRP proteins that confer resistance to topoisomerase poisons and contrasts with most PRP proteins, which are typically monomeric.
蛋白质AlbG是一种针对白叶枯菌素的自我抗性因子，白叶枯菌素是一种由白叶黄单胞菌产生的具有抗生素和植物毒性的非核糖体编码的杂合聚酮肽。一级序列分析表明，AlbG是五肽重复蛋白家族（PRP）的成员。利用在家用光源上从单个醋酸三甲基铅衍生物收集的数据，通过单波长反常散射（SAD）相位法在2.0 Å分辨率下测定了来自白叶黄单胞菌的AlbG的结构。AlbG折叠成一个由大约八个半规则螺旋组成的右手四边形β-螺旋。β-螺旋的规则性因第4和第5个螺旋之间的β-螺旋中有一个大环/偏差而受到破坏。β-螺旋的C末端由一个二聚化模块封端，形成一个具有110 Å半共线β-螺旋轴的二聚体。这种二聚体形成方式似乎是所有赋予对拓扑异构酶毒物抗性的PRP蛋白所共有的，与大多数通常为单体的PRP蛋白形成对比。
