Novel antimicrobials targeting type IV pilus and type 2 secretion systems

 描述（由申请人提供）：细菌病原体具有保守的复杂分子机器，这些分子机器是引起疾病所必需的。在这些机器中，有那些组成IV型菌毛（T4 P）生物发生装置和相关的II型分泌（T2 S）机器。T4 Ps是许多重要细菌病原体粘附和宿主定殖所必需的表面附属物; T2 S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产生T4 Ps。两种机器共有的组分之一是前菌毛蛋白肽酶，其特异性地从前菌毛蛋白去除特征性N-末端信号序列并使新生氨基末端N-甲基化。这些酶是高度保守的，T4 P和T2 S功能绝对需要的，并代表了一类新的中性pH天冬氨酸肽酶，不像哺乳动物酶。因此，它们是新药发现的理想靶点。我们设计了一个体内Föster共振能量转移（FRET）系统，该系统由在大肠杆菌中表达的三种重组蛋白组成。大肠杆菌：前菌毛蛋白肽酶、与增强型黄色荧光蛋白（eYFP）融合的前菌毛蛋白和与dsRed融合的前菌毛蛋白结合的必需装配蛋白。通过前菌毛蛋白肽酶切割前菌毛蛋白融合蛋白释放eYFP并阻止与dsRed的FRET。如果前菌毛蛋白肽酶因突变而失活，则发生FRET。我们将采用这种非常敏感的系统和相关的更简单的系统，依赖于荧光各向异性，以开发体外高通量小分子筛选，以确定前菌毛蛋白肽酶抑制剂的候选者。二级试验将确定特异性和活性谱。最初的努力将提供候选物，这些候选物随后将进行进一步的化学精制，以增强对整个细菌的效力、特异性和活性。最后，（a）将使用已建立的铜绿假单胞菌肺炎鼠模型（其中疾病需要T4 Ps）将先导化合物推进临床前试验。最终，我们的目标是发现一种全新的治疗类抗病毒剂，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.