Smith Mark A, Coinçon Mathieu, Paschos Athanasios, Jolicoeur Benoit, Lavallée Pierre, Sygusch Jurgen, Baron Christian
Department of Biochemistry, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada.
Chem Biol. 2012 Aug 24;19(8):1041-8. doi: 10.1016/j.chembiol.2012.07.007.
Secretion systems translocate virulence factors of many bacterial pathogens, enabling their survival inside the host organism. Consequently, inhibition strongly attenuates pathogenicity and can be considered a target for novel antimicrobial drugs. The type IV secretion system (T4SS) of the intracellular pathogen Brucella is a prerequisite for its virulence, and in this work we targeted the interactions of the essential assembly factor protein, VirB8, using small-molecule inhibitors. High-throughput screening identified several potent and specific inhibitors, and the target-binding site of these inhibitors was identified by X-ray crystallography, in silico docking, and analysis of the derivates of the inhibitor B8I-2. VirB8 interaction inhibitors bind to a surface groove opposite to the dimerization interface, and by varying the binding-site residues, we were able to determine which residues are required for inhibitor activity. E115 and K182 were found to be especially important, and changes at R114, Y229, and L151 also reduced inhibitor efficiency.
分泌系统可转运多种细菌病原体的毒力因子，使其能够在宿主体内存活。因此，抑制作用会大大减弱致病性，可被视为新型抗菌药物的一个靶点。细胞内病原体布鲁氏菌的IV型分泌系统（T4SS）是其毒力的先决条件，在这项研究中，我们使用小分子抑制剂靶向关键组装因子蛋白VirB8的相互作用。高通量筛选鉴定出了几种强效且特异性的抑制剂，并通过X射线晶体学、计算机对接以及对抑制剂B8I-2衍生物的分析确定了这些抑制剂的靶点结合位点。VirB8相互作用抑制剂与二聚化界面相对的表面凹槽结合，通过改变结合位点残基，我们能够确定哪些残基是抑制剂活性所必需的。发现E115和K182尤为重要，R114、Y229和L151处的变化也会降低抑制剂效率。
