INHIBITION OF ACETYLCHOLINESTERASE BY FASCICULIN MUTANTS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 自1993年以来，PI一直参与乙酰胆碱酯酶(AChE)和其他系统的分子动力学分析-其中一些系统是在PSC进行的。这种酶在神经信号到肌肉收缩的传递中起着至关重要的作用，是神经毒气毒剂以及用于治疗阿尔茨海默病(S病)的药物的靶标。发酵素(Fas)是蛇毒的一种成分，也是AChE的靶标。Sussman等人的一篇手稿，由PI审阅，目前正在出版中，报告说某些Fas突变体更能与AChE结合，但它们的亲和力不能通过检查静态晶体结构来解释。我们在单CPU SGI机器上对AChE-Fas复合体进行了CHARMm模拟，表明这些差异是由突变引起的主链扭曲造成的。我们正在寻求PSC访问，以扩展这些CHARMm模拟，并更好地解释为什么一些突变增强，而另一些突变抑制结合，与基于晶体结构静态分析的预测相反。这些结论将与蛋白质设计的许多问题相关。拟议的研究将由宾夕法尼亚大学生物化学和分子生物物理学专业的一名研究生在PI的监督下进行。这个学生已经在内部机器上执行CHARMm模拟，因此在PSC机器上的开发时间将是最短的。该项目将持续到9月中旬，也可能是12月。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The PI has been involved with molecular dynamics analyses of Acetylcholinesterase (AChE) since 1993, and other systems - some of which were performed at the PSC. This enzyme is critically involved in the transmission of nerve signals to muscle contraction, and it is the target of nerve gas agents as well as drugs used to treat Alzheimer(s disease. Fasciculin (Fas) is a component of snake venom that also targets AChE. A manuscript by Sussman et al, reviewed by the PI, and currently _in press_, reports that certain Fas mutants bind more avidly to AChE, but their affinity is not explained by examination of the static crystal structures. We have run CHARMm simulations of the AChE-Fas complex on a single-CPU SGI machine that suggest the discrepancies are a consequence of main chain distortions induced by the mutations. We are seeking PSC access to extend these CHARMm simulations and better explain why some mutations enhance, while others inhibit binding, contrary to predictions based on static analysis of the crystal structures. The conclusions will be relevant to many questions about protein design. The proposed studies will be performed by a graduate student in Biochemistry and Molecular Biophysics at the University of Pennsylvania, under the supervision of the PI. This student is already performing CHARMm simulations on in-house machines, so development time on PSC machines will be minimal. The project will continue until mid-September, or possibly December.