Fighting Antibiotic Resistant Tuberculosis: Structural Studies of an Mmpl

抗生素的广泛使用推动了许多致病菌耐药机制的进化，其水平已接近全球卫生危机状态。值得关注的是结核分枝杆菌的多重、极端和完全耐药菌株的出现，结核分枝杆菌是结核病的病原，也是世界范围内传染病相关死亡的主要原因。由于新型抗结核药物发现不足，以及对在分子水平上产生耐药性的机制了解不完全，情况进一步恶化。牛津大学的CRyPTIC计划是国际抗结核反应的一部分，它正在使用100万株结核分离株的全基因组测序来编目已知和新的抗结核靶点的耐药突变。该项目与CRyPTIC合作，旨在结合结构生物学、功能生物化学和计算方法，开始对抗耐抗生素结核病。最初的工作将集中在结核分枝杆菌膜蛋白的结构和功能特征-以及密切相关的谷氨酸分枝杆菌同源物-在细胞壁生物合成（糖脂转运蛋白MmpL3， CmpL1和CmpL3）或药物外排（MmpL5和NCgl-1194）中起作用。这两类蛋白都与抗结核耐药性和/或结核分枝杆菌生存能力有关；因此代表了可以开发新抗生素的假定目标。应用类似的方法，以及互补的硅自由能计算，还将寻求对KatG（过氧化氢酶-过氧化物酶）的隐性鉴定突变如何能够促进对一线抗结核异烟肼（INH）的耐药性的机制理解。随着项目的进展，将进一步研究与CRyPTIC耐药有关的新蛋白。优先领域：抗击抗菌素耐药性；BfH, ENWW

Widespread use of antibiotics has driven evolution of resistance mechanisms in many pathogenic bacteria, approaching levels that warrant global health crisis status. Of notable concern is the emergence of multi-, extremely and totally-drug resistant strains of M.tuberculosis-the aetiological agent of tuberculosis (TB) disease and the leading cause of infectious disease-associated mortality worldwide. The situation has been further compounded by insufficient discovery of novel antituberculars, as well as an incomplete understanding of the mechanisms by which resistance is achieved at the molecular level. Spearheading part of an international anti-TB response, the Oxford-based CRyPTIC initiative is using whole-genome sequencing of >100,000 TB isolates to catalogue resistance mutations in both known and novel antitubercular targets. In collaboration with CRyPTIC, this project aims to use a combination of structural biology, functional biochemistry and computational approaches to begin combatting antibiotic resistant TB. Initial efforts will focus on the structural and functional characterisation of M.tuberculosis membrane proteins-alongside closely related C.glutamicum homologues-functioning in cellwall biosynthesis (the glycolipid transporters MmpL3, CmpL1 & CmpL3) or drug-efflux (MmpL5 & NCgl-1194). Both classes of protein have been implicated in antitubercular resistance and/or are required for M.tuberculosisviability; thus representing putative targets against which new antibiotics could be developed. Applying similar methodology, alongside complementary in silico free-energy calculations, a mechanistic understanding of how CRyPTIC-identified mutations in KatG (a catalase-peroxidase) are able to promote resistance to the front-line antitubercular isoniazid (INH) will also be sought. As the project progresses, new proteins implicated in resistance by CRyPTIC will be additionally investigated.BBSRC Priority Area: Combatting Antimicrobial Resistance; BfH, ENWW