INHIBITION OF ACETYLCHOLINESTERASE BY FASCICULIN MUTANTS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 PI自1993年以来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关键作用，它是神经毒气剂和治疗阿尔茨海默病的药物的目标。Fasciculin（Fas）是蛇毒的一种成分，也靶向AChE。Sussman等人的手稿（PI审查，目前正在出版）报告称，某些Fas突变体更积极地与AChE结合，但其亲和力无法通过检查静态晶体结构来解释。我们已经运行CHARMm模拟的乙酰胆碱酯酶-Fas复合物上的单CPU SGI机器，这表明差异是由突变引起的主链扭曲的后果。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，而另一些抑制结合，与基于晶体结构的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有关。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研究生在PI的监督下进行。该学生已经在内部机器上进行CHARMm模拟，因此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. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. 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.