Mechanism of Intrinsic Hydrolysis in Small GTPases

小gtpase超家族包括五组不同的蛋白质，它们共同涉及细胞功能的几乎所有方面。它们与鸟苷二磷酸（GDP）结合时无活性，与三磷酸形式（GTP）结合时具有功能活性。在过去的25年里，人们对gtp酶进行了深入的研究，并且对其进行调控的一般机制已被广泛接受，以至于它经常出现在生物化学和细胞生物学的教科书中。该项目基于一种范式转换假设，该假设在特定情况下修改了某些gtp酶的这种机制，阐明了与不同形式的gtp结合蛋白相关的微妙调节水平。在这个项目下进行的研究集中在Ras GTPase作为一个模型来阐明其功能在新发现的环境中失活的化学机制，在第二个GTPase上测试机制，并使用计算方法来查看整个家族的序列模式，挖掘GTPase结构数据库，以评估最近在NSF支持下发现的调节机制的一般性。该项目将使用多学科方法，重点是x射线晶体学，中子晶体学，量子力学/分子力学计算（QM/MM），动力学实验和gtpase超家族的结晶学水分析，使用我们的内部程序检测相关溶剂位置（DRoP），该程序是由以前的NSF资助开发的。更广泛的影响该项目支持三名研究生，他们将在一个蓬勃发展和多样化的研究和教育环境中接受培训，在这个环境中，在学术阶梯的各个层次，指导是团队合作的一个重要方面。每个人都将在项目中与一名本科生密切合作并指导他们。本科生是研究的组成部分，参与合作项目，支持东北大学本科生在实验室长期全职工作。PI正在通过东北大学教师研讨会项目与少数族裔服务机构建立牢固的联盟，该项目是她来到东北大学后发起的。目标是增加申请化学生物学博士课程的申请人的多样性，同时吸引少数民族学生参与令人兴奋的研究，这将促进对科学的长期承诺。通过与少数民族优质教育网络（QEM）的伙伴关系，PI正在向没有研究机会的少数民族服务机构的本科生伸出援助之手。在项目期间，将支持两名少数民族本科生进行暑期研究。每个项目都将有一个研究生导师，并将与项目负责人密切合作，以确保有效的学习和实验室的生产力。

Intellectual MeritThe superfamily of small GTPases includes five distinct groups of proteins that collectively touch on virtually all aspects of cellular function. They are inactive when bound to guanosine diphosphate (GDP) and functionally active when bound to the triphosphate form (GTP). GTPases have been very well studied for over 25 years and a general mechanism through which they are regulated is so well accepted that it routinely appears in Biochemistry and Cell Biology texts books. This project is based on a paradigm-shifting hypothesis that modifies this mechanism for some GTPases under particular circumstances, elucidating a subtle level of regulation associated with different forms of the GTP-bound protein. The research performed under this project focuses on Ras GTPase as a model for elucidating the chemical mechanism through which its function is deactivated in the newly discovered context, tests the mechanism on a second GTPase and uses computational approaches to look at sequence patterns across the family, mining the database of GTPase structures to assess the generality of the regulatory mechanism recently uncovered with aid from previous NSF support. This project will use multidisciplinary approaches focused on X-ray crystallography, neutron crystallography, quantum mechanics/molecular mechanics calculations (QM/MM), kinetic experiments and a crystallographic water analysis across the superfamily of GTPases using our in-house program Detection of Related Solvent Positions (DRoP) developed with previous NSF funding.Broader ImpactThe project supports three graduate students who will be trained in a thriving and diverse research and educational environment where mentoring is an important aspect of teamwork in the group at all levels of the academic ladder. Each will work closely with and mentor an undergraduate student on the project. Undergraduates constitute and integral part of the research, engaged in the Co-op program that supports Northeastern undergraduates for extended period of full time in the laboratory. The PI is developing strong alliances with minority serving institutions through the Northeastern Faculty Seminar Program, which she has initiated since arriving at Northeastern. The goal is to increase the diversity of applicants to the Ph.D. program in Chemical Biology while engaging minority students in exciting research that will promote long-term commitment to science. Through a partnership with Quality Education for Minorities (QEM) network the PI is reaching out to undergraduates from minority-serving institutions that do not have research opportunities. Two minority undergraduate students will be supported for summer research during the duration of the project. Each will have a graduate student mentor on the project and will work closely with the PI to assure effective learning and productivity in the laboratory.