Allosteric elements in the superfamily of small GTPases

标题：小gtpase超家族中的变构元件小gtpase是几乎涉及细胞功能所有方面的蛋白质，从细胞增殖的控制、细胞死亡的调节、运动、细胞内含有分子货物的膜泡的运输以及细胞质和细胞核之间的分子运输。它们的活性是由与活性位点结合的分子（GTP）转化为GDP和无机磷酸盐来调节的。它们属于一组150多个蛋白质，分为5个家族：Ras、Rho、Rab、Arf和Ran。本研究项目的目标是确定Ras， Rho和Arf家族（在细胞膜上发现的蛋白质家族）中的代表性蛋白质如何进化出与其不同功能相关的特定结构细节。研究人员将测试与细胞膜的相互作用如何影响这些小gtpase的功能。这将使用多学科方法来完成，该方法基于互补的最先进的生物物理和生化实验，旨在阐明这些蛋白质工作的基本分子机制。除了继续促进多样化的实验室和部门环境，该项目将在其中进行，还将有一个新的未来教师奖学金指导项目，与东北大学的ADVANCE项目相关。gtpase Ras超家族中的蛋白质（小gtpase）在细胞中具有多种功能，它们通过严格调节的机制从活性gtp结合状态切换到非活性gdp结合状态。现在有大量证据表明，通过变构调节将膜相互作用热点与活性位点连接起来，与膜的相互作用是调节机制的一个组成部分。在这个项目中，研究人员旨在确定这些相互作用的性质，并绘制超家族的三个代表性成员：HRas， RhoA和Arf1的变构途径。研究人员假设，特定的膜元件在调节g蛋白超家族大多数分支的功能中起关键作用。他们将通过使用一系列磷脂头组模拟物来确定膜组分与HRas， RhoA和Arf1的结合特异性，并通过研究策略设计的突变体对状态的构象集合和相关水解速率的影响来验证这一假设。这将使用x射线晶体学，水解率测量，广角区域（WAXS）的溶液散射实验和加速MD （aMD）模拟的组合来完成，每种方法都提供了一个视角，共同将导致迄今为止尚未在超家族中探索的调节机制的机械视图。

Title: Allosteric elements in the superfamily of small GTPasesThe Small GTPases are proteins involved in virtually all aspects of cellular function, from the control of cell proliferation, regulation of cell death, motility, transport of membrane vesicles containing molecular cargo within the cell and transport of molecules between the cell cytoplasm and nucleus. Their activity is regulated by conversion of a molecule (GTP) bound to their active site to GDP and inorganic phosphate. They belong to a group of over 150 proteins classified into 5 families: Ras, Rho, Rab, Arf and Ran. The goal of this research project is to determine how representative proteins in the Ras, Rho and Arf families, protein families that are found on the cell membrane, have evolved specific structural details associated with their distinct functions. The investigators will test how interactions with the cell membrane affect the function of these small GTPases. This will be done using a multidisciplinary approach based on complementary state of the art biophysical and biochemical experiments designed to elucidate the fundamental molecular mechanisms through which these proteins work. In addition to continuing to promote diverse laboratory and departmental environments in which this project will be conducted, there will be a new Future Faculty Fellowship mentoring program at the university level associated with the ADVANCE program at Northeastern. Proteins in the Ras superfamily of GTPases (Small GTPases) are involved in vastly diverse functions in the cell, where they work through a tightly regulated mechanism of switching from an active GTP-bound state to an inactive GDP-bound state. There is now substantial evidence that interaction with the membrane is an integral part of the regulatory mechanism through allosteric modulation linking membrane-interacting hot spots to the active site. In this project, investigators aim to determine the nature of these interactions and to map the allosteric pathways in three representative members of the superfamily: HRas, RhoA and Arf1. The investigators hypothesize that specific membrane elements play a key role in regulating the function of G-proteins across most branches of the superfamily. They will will test this hypothesis by using a series of phospholipid head group mimics to determine the binding specificities of membrane components to HRas, RhoA and Arf1 and by studying the effects of strategically designed mutants on the conformational ensemble of states and associated hydrolysis rates. This will be done using a combination of X-ray crystallography, hydrolysis rate measurements, solution scattering experiments in the wide angle regime (WAXS) and accelerated MD (aMD) simulations, each method providing a perspective that together will lead to a mechanistic view of regulatory mechanisms that have thus far been unexplored within the superfamily.