Novel antimicrobials targeting type IV pilus and type 2 secretion systems

 描述(申请人提供)：细菌病原体保存了导致疾病所需的复杂分子机器。在这些机器中，有组成IV型菌毛(T4P)生物发生装置和相关的II型分泌物(T2S)机器的机器。T4P是许多重要细菌病原体黏附和寄主定植所必需的表面附属物；T2S系统输出对许多疾病至关重要的毒素。鲍曼不动杆菌、铜绿假单胞菌和淋病奈瑟菌都能产生T4P。在这两台机器的共同组件中，有一种前胶蛋白肽酶，它专门从前胶蛋白中移除特有的N-末端信号序列，并对新生的氨基末端进行N-甲基化。这些酶高度保守，是T4P和T2S功能所必需的，代表了一类新的中性pH天冬氨酸肽酶，与哺乳动物的酶不同。因此，它们是新药发现的理想目标。我们设计了一个体内Föster共振能量转移(FRET)系统，该系统由三个在大肠杆菌中表达的重组蛋白组成：前毛细蛋白多肽酶，前毛细蛋白与增强的黄色荧光蛋白(EYFP)融合，以及前毛细蛋白与dsRed融合的基本组装蛋白。Pre-Pilin多肽酶切割Pre-Pilin融合蛋白释放EYFP，并防止与dsRed的FRET。如果Pre-Pilin多肽酶因突变而失活，则会发生FRET。我们将采用这个极其敏感的系统和一个相关的更简单的系统，依赖于荧光各向异性来开发体外高通量小分子筛选，以识别Pre-Pilin肽酶抑制剂候选。二次化验将确定活性的特异性和光谱。最初的努力将提供候选，随后将进行进一步的化学精炼，以提高对整个细菌的效力、特异性和活性。最后，(A)先导化合物(S)将使用已建立的铜绿假单胞菌肺炎小鼠模型进行临床前测试，在该模型中，疾病需要T4P。最终，我们的目标是发现一种全新的治疗类抗病毒药物，以改善人类健康。

 DESCRIPTION (provided by applicant): Bacterial pathogens have conserved complex molecular machines that are required to cause disease. Among these machines are those that make up a type IV pilus (T4P) biogenesis apparatus and the related type II secretion (T2S) machine. T4Ps are surface appendages essential for adherence and host colonization by many important bacterial pathogens; T2S systems export toxins that are critical for many diseases. Acinetobacter baumanii, Pseudomonas aeruginosa, and Neisseria gonorrhoeae all produce T4Ps. Among the components common to both machines is a pre-pilin peptidase enzyme that specifically removes the characteristic N-terminal signal sequence from pre-pilin proteins and N-methylates the nascent amino terminus. These enzymes are highly conserved, absolutely required for T4P and T2S function, and represent a novel class of neutral pH aspartic acid peptidases that do not resemble mammalian enzymes. As such, they are ideal targets for new drug discovery. We have devised an in vivo Föster resonance energy transfer (FRET) system comprised of three recombinant proteins expressed in E. coli: the pre-pilin peptidase, the pre-pilin protein fused to enhanced yellow fluorescent protein (eYFP), and an essential assembly protein to which the pre-pilin binds fused to dsRed. Cleavage of the pre-pilin fusion protein by the pre-pilin peptidase releases eYFP and prevents FRET with dsRed. If the pre-pilin peptidase is inactivated by mutation, then FRET occurs. We will adapt this extremely sensitive system and a related even simpler system that relies on fluorescence anisotropy to develop in vitro high-throughput small molecule screens to identify pre-pilin peptidase inhibitor candidates. Secondary assays will establish specificity and spectrum of activity. The initial effort will provie candidates that will subsequently subjected to further chemical refinement to enhance potency, specificity and activity against whole bacteria. Finally, (a) lead compound(s) will be advanced to preclinical testing using an established murine model of P. aeruginosa pneumonia in which T4Ps are required for disease. Ultimately, the goal is to discover an entirely novel therapeutic class of anti-virulence agents to improve human health.