A combined, chemical-microbiology approach to understand the function of novel antibiotic resistance determinant in Gram-negative bacteria.

国王学院伦敦和英国公共卫生部之间正在进行的合作最近确定了一类调节蛋白，其可能在重要的革兰氏阴性病原体肺炎克雷伯氏菌中通过直接结合特定类型的抗生素介导内在抗性中发挥重要作用。我们现在已经确定了两个不相关的化学实体，但具有共同的分子靶点（DNA-促旋酶），其抗性似乎由该调节剂介导。这提出了这种蛋白质是多药物结合结构域的可能性，能够结合和响应广泛的抗生素，或者能够在功能上模拟回旋酶结合口袋。这两种可能性都很有趣，我们计划使用同源建模和化学合成的组合，再加上分子微生物学技术，以提供工具来解开这些蛋白质的作用机制。该蛋白质家族广泛分布于一系列革兰氏阴性病原体中，并且在革兰氏阳性病原体中也对预测的结构域结构进行了一些修饰。它们也存在于许多聚酮合酶或非核糖体肽脱氢酶聚集的细菌中，在那里它们可能作为免疫蛋白与尚未鉴定的化合物一起起作用。这可能代表了一系列耐药决定因素，这些决定因素影响了对现有和新型抗生素的内在敏感性。它也可以代表一系列在体外或体内使用的亲和配体，其可以用于鉴定和鉴定来自各种来源的新型抗微生物化合物。

An ongoing collaboration between King's College London and Public Health England has recently identified a class of regulator proteins that may play an important role in mediating intrinsic resistance, via direct binding to particular types of antibiotic, in the important Gram-negative pathogen Klebsiella pneumoniae. We have now identified two unrelated chemical entities, but with a shared molecular target (DNA-gyrase), for which resistance appears to be mediated by this regulator. This raises the possibility that this protein is either a multidrug binding domain, capable of binding and responding to a wide range of antibiotics or is able to functionally mimic the gyrase-binding pocket. Both of these possibilities are intriguing, and we plan to use a combination of homology modelling and chemical synthesis, coupled with molecular microbiology techniques to provide tools to unpick the mechanism of action of these proteins. This family of proteins is widely distributed across a range of Gram-negative pathogens and with, some modifications to predicted domain structure, in Gram-positive pathogens also. They are also found in a number of bacteria clustered with polyketide synthase or non-ribosomal peptide synthases, where they may act as immunity proteins with, as yet, unidentified compounds. This may represent a pool of resistance determinants that impact on intrinsic susceptibility to existing and novel antibiotics. It may also represent a series of affinity ligands to be used in vitro or in vivo, that could be used to identify and characterise novel antimicrobial compounds from a variety of sources.