Mechanism of Intrinsic Hydrolysis in Small GTPases

小GTP酶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。当与鸟苷二磷酸（GDP）结合时无活性，当与三磷酸形式（GTP）结合时有功能活性。GTP酶已经被很好地研究了超过25年，并且它们被调节的一般机制被广泛接受，以至于它经常出现在生物化学和细胞生物学教科书中。该项目基于范式转变假设，该假设在特定情况下修改了某些GTPases的这种机制，阐明了与不同形式的GTPases结合蛋白相关的微妙调节水平。在该项目下进行的研究重点是Ras GTdR作为阐明其功能在新发现的背景下失活的化学机制的模型，在第二个GTdR上测试该机制，并使用计算方法来查看整个家族的序列模式，挖掘GTdR结构的数据库，以评估最近在NSF支持的帮助下发现的调控机制的一般性。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），使用我们的内部程序相关溶剂位置检测（DRoP）进行GTP酶超家族的动力学实验和晶体学水分析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指导是团队合作的一个重要方面，在各个层次的学术阶梯。每个人都将与该项目的本科生密切合作并指导他们。本科生构成研究的一个组成部分，从事合作社计划，支持东北大学生在实验室全职延长一段时间。PI正在通过东北教师研讨会计划与少数民族服务机构建立强大的联盟，该计划是她自抵达东北以来发起的。我们的目标是增加博士申请人的多样性。在化学生物学计划，同时从事令人兴奋的研究，将促进长期致力于科学少数民族学生。通过与少数群体优质教育网络的伙伴关系，PI正在接触没有研究机会的少数群体服务机构的本科生。两名少数民族本科生将在项目期间获得夏季研究的支持。每个项目都将有一名研究生导师，并将与PI密切合作，以确保实验室的有效学习和生产力。

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.