Structural Basis of Retroviral Restriction by TRIM5alpha

TRIM5alpha 限制逆转录病毒的结构基础

• 批准号: 8055204
• 负责人: DMITRI N IVANOV
• 金额: $ 12.31万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-23 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8055204
• 关键词: base

DESCRIPTION (provided by applicant): TRIM5alpha proteins bind retroviral capsids after cell entry and restrict retroviral infection by blocking reverse transcription and/or integration of the viral genetic material {Nisole, 2005 #305; Towers, 2007 #310}. This novel mechanism of cellular immunity against retroviruses appears to determine the species tropism of the primate immunodeficiency viruses active today. Experimental evidence suggests that species-specific differences in TRIM5alpha activity arise from differences in TRIM5alpha affinity for the capsid. Capsid recognition is mediated by the B30.2 domain of TRIM5alpha, but the structural basis of TRIM5alpha-CA interactions is unknown. The central hypothesis of this proposal is that structural differences at the B30.2- capsid interface explain species-specific differences in TRIM5alpha activity. In order to elucidate the mechanism of the TRIM5alpha-capsid binding I will pursue the following objectives: 1. TRIM5alpha B30.2 domain structure: Expression and purification protocols will be developed in order to produce and label TRIM5alpha proteins in sufficient quantities for structural and biophysical studies. Structures of the rhesus and human TRIM5alpha B30.2 domains will be determined using NMR. Effects of the TRIM5alpha specificity-altering mutations on B30.2 structure will be investigated. Structural differences between rhB30.2 and huB30.2 responsible for the inability of the huTRIM5alpha to restrict HIV will be determined. Dynamic parameters of the B30.2 variable loops involved in capsid binding will be measured. 2. Molecular basis of capsid recognition by TRIM5alpha: Interaction surfaces involved in B30.2-capsid binding will be identified using NMR. Relative orientation of B30.2 and CA in the complex will be determined. A model of the B30.2-CA complex will be produced and key B30.2-CA interactions identified. Structural models will be tested using mutagenesis, biophysical and in-vivo assays. NMR will be used to detect cooperativity between CypA-CA and TRIM5alpha-CA binding and to check whether CypA-catalyzed cis-trans isomerisation of the G89-P90 peptide bond of the HIV-1 capsid affects B30.2-CA interactions. PUBLIC HEALTH RELEVANCE: The AIDS epidemic caused by the HIV retrovirus is one of the leading threats posed to global health by an infectious agent. Higher organisms have multiple layers of immunity against retroviral pathogens, but the HIV has evolved specific mechanisms to overcome host defenses. The goal of this proposal is to investigate the mechanism of retroviral restriction by the primate TRIM5alpha proteins, to elucidate viral evasion strategies and to explore whether the inability of the human TRIM5alpha to restrict HIV could be restored by pharmacological means.

描述（由申请人提供）：TRIM5α蛋白在进入细胞后结合逆转录病毒衣壳，并通过阻断病毒遗传物质的逆转录和/或整合来限制逆转录病毒感染{Nisole，2005#305；塔，2007 #310}。这种针对逆转录病毒的细胞免疫的新机制似乎决定了当今活跃的灵长类免疫缺陷病毒的物种向性。实验证据表明，TRIM5α 活性的物种特异性差异源于 TRIM5α 对衣壳亲和力的差异。衣壳识别由 TRIM5alpha 的 B30.2 结构域介导，但 TRIM5alpha-CA 相互作用的结构基础尚不清楚。该提议的中心假设是 B30.2-衣壳界面的结构差异解释了 TRIM5alpha 活性的物种特异性差异。为了阐明 TRIM5alpha-衣壳结合的机制，我将追求以下目标： 1. TRIM5alpha B30.2 结构域结构：将开发表达和纯化方案，以便生产和标记足够数量的 TRIM5alpha 蛋白，用于结构和生物物理学研究。恒河猴和人 TRIM5alpha B30.2 结构域的结构将使用 NMR 确定。将研究 TRIM5alpha 特异性改变突变对 B30.2 结构的影响。将确定 rhB30.2 和 huB30.2 之间导致 huTRIM5alpha 无法限制 HIV 的结构差异。将测量参与衣壳结合的 B30.2 可变环的动态参数。 2. TRIM5alpha 衣壳识别的分子基础：将使用 NMR 鉴定参与 B30.2-衣壳结合的相互作用表面。将确定复合物中 B30.2 和 CA 的相对方向。将生成 B30.2-CA 复合物模型并确定关键的 B30.2-CA 相互作用。将使用诱变、生物物理和体内测定来测试结构模型。 NMR 将用于检测 CypA-CA 和 TRIM5alpha-CA 结合之间的协同性，并检查 CypA 催化的 HIV-1 衣壳 G89-P90 肽键的顺反异构化是否影响 B30.2-CA 相互作用。公共卫生相关性：由 HIV 逆转录病毒引起的艾滋病流行是传染源对全球健康构成的主要威胁之一。高等生物对逆转录病毒病原体具有多层免疫力，但艾滋病毒已经进化出特定的机制来克服宿主的防御。本提案的目的是研究灵长类TRIM5α蛋白限制逆转录病毒的机制，阐明病毒逃避策略，并探索是否可以通过药理学手段恢复人类TRIM5α限制HIV的能力。