Mapping the Binding Surfaces of Ras and Related GTPases

绘制 Ras 和相关 GTP 酶的结合表面图谱

• 批准号: 7092074
• 负责人: CARLA MATTOS
• 金额: $ 19.8万
• 依托单位: NORTH CAROLINA STATE UNIVERSITY RALEIGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7092074
• 关键词: X ray crystallography; binding sites; enzyme structure; guanine nucleotide binding protein; guanosinetriphosphatases; mutant; nonwater solvent; oncoproteins; protein binding; protein structure function; solvents; structural biology

DESCRIPTION (provided by applicant): Ras is a small GTPase involved in the control of cell proliferation and is the focus of this research proposal. Several of its mutants have been directly linked to human cancers, as they remain in an activated state that leads to uncontrolled cell division. Ras is a member of a group of structurally similar proteins involved in highly specific interactions with regulatory agents that control their ability to bind to target proteins within complicated signal transduction cascades. Our objective is to decipher the rules for molecular recognition within the Ras family of GTPases. These rules will be used in the future to guide the design of specific ligands targeted towards the defective oncogenic Ras proteins. Our approach is based on a comparative analysis of the binding surfaces of Ras, two of its most common oncogenic mutants and of its close family members Rap and Ral. Conventional X-ray crystallography will be combined with the multiple solvent crystal structures (MSCS) method where organic solvent molecules are used as probes to the molecular surface features of protein binding sites. Using these methods, we plan to create "functionality maps" of the binding surfaces of Ras, RasG12V, RasQ61L, Rap and Ral. We will accomplish our goals through four specific aims. First, we will use the MSCS method to characterize both the primary target recognition sites and the putative secondary binding sites on Ras, Rap and Ral, so that the common binding site features across the family can be distinguished from those that are specific to each family member. Second, we will use the MSCS method to determine key differences in the binding site of Ras due to the oncogenic mutations G12V and Q61L. Third, we will solve the crystal structure of Ral and of its complex with the Ral minimum binding domain of its target Ral Binding Protein 1 (RalBP1). We will compare this structure with the analogous complexes for Ras (Ras/RalGDS) and Rap (Rap/Raf), which have previously been published. Fourth, we will combine the results from the first three aims to delineate areas specific to the Ras, and, in particular, to its oncogenic mutants. The goal is to provide key information for ligand design and discovery that is based on multiple structures that offer multiple perspectives.

描述（由申请人提供）：Ras 是一种参与细胞增殖控制的小型 GTP 酶，是本研究计划的重点。它的几个突变体与人类癌症直接相关，因为它们保持激活状态，导致不受控制的细胞分裂。 Ras 是一组结构相似的蛋白质的成员，参与与调节剂的高度特异性相互作用，这些调节剂控制其在复杂的信号转导级联中与靶蛋白结合的能力。我们的目标是破译 Ras GTPases 家族中的分子识别规则。这些规则将来将用于指导针对有缺陷的致癌 Ras 蛋白的特定配体的设计。我们的方法基于对 Ras（Ras 的两种最常见的致癌突变体）及其密切家族成员 Rap 和 Ral 的结合表面的比较分析。传统的 X 射线晶体学将与多溶剂晶体结构 (MSCS) 方法相结合，其中有机溶剂分子用作蛋白质结合位点分子表面特征的探针。使用这些方法，我们计划创建 Ras、RasG12V、RasQ61L、Rap 和 Ral 结合表面的“功能图”。我们将通过四个具体目标来实现我们的目标。首先，我们将使用 MSCS 方法来表征 Ras、Rap 和 Ral 上的主要目标识别位点和假定的次级结合位点，以便可以将整个家族的常见结合位点特征与每个家族成员特有的结合位点特征区分开来。其次，我们将使用 MSCS 方法来确定由于致癌突变 G12V 和 Q61L 导致的 Ras 结合位点的关键差异。第三，我们将解析 Ral 及其与目标 Ral 结合蛋白 1 (RalBP1) 的 Ral 最小结合域的复合物的晶体结构。我们将将此结构与之前发表的 Ras (Ras/RalGDS) 和 Rap (Rap/Raf) 的类似配合物进行比较。第四，我们将结合前三个目标的结果来描绘 Ras 特有的区域，特别是其致癌突变体。目标是为基于提供多种视角的多种结构的配体设计和发现提供关键信息。