HIV-1 Capsid Protein/Cyclophilin-A Complex : A Structural Study

描述（由申请人提供）：人类免疫缺陷病毒1型（HIV-1）在其生命周期中利用大量宿主细胞蛋白。其中较突出的蛋白质是人亲环素A（CypA），其被病毒用于最佳感染性和病毒复制。CypA的一些假定的功能已被假定，但我们的理解，它在HIV-1生命周期中的确切作用仍然是初步的。作为对PA-06-388公告的回应，在当前的R21/R33申请中提出了一项组合溶液NMR和生物物理模拟研究，以确定与亲环素A结合的HIV-1衣壳蛋白（CA）的详细三维结构。由于其固有的灵活性，寡聚化的倾向，以及其在溶液中的单体-二聚体平衡，野生型全长CA结合CypA的结构研究已经通过晶体学和NMR光谱学挫败了尝试。因此，在这项调查中，我们将研究CypA/CA复合物使用的双突变CA作为单体存在于溶液中，并保留所有的野生型CA的关键特性，包括装配活动。利用3D/4D-NMR光谱，残余偶极耦合测量和生物物理模拟，我们将确定详细的解决方案结构的双突变CA，其复杂的人CypA。CypA/CA复合物的详细结构的知识将提供一个结构生物学基础，提高我们的理解CypA的确切作用，在病毒的生命周期。这种结构也可能有助于开发具有治疗潜力的CypA-CA相互作用的新抑制剂。公共卫生相关性：这项调查的目的是在确定详细的三维结构的人亲环素A绑定到一个突变的衣壳蛋白的HIV-1病毒使用相结合的解决方案NMR和生物物理模拟的方法。

DESCRIPTION (provided by applicant): The human immunodeficiency virus type 1 (HIV-1) exploits a large number of host cellular proteins in its life cycle. Among the more prominent proteins is the human cyclophilin A (CypA) which is utilized by the virus for optimal infectivity and viral replication. A number of putative functions have been postulated for CypA but our understanding of its precise role within HIV-1 life cycle is still rudimentary. In response to the PA-06-388 announcement, a combined solution NMR and biophysical simulation investigation is proposed in the current R21/R33 application to determine the detailed three dimensional structure of the HIV-1 capsid protein (CA) bound to cyclophilin A. Because of its inherent flexibility, tendency to oligomerize, and its monomer-dimer equilibrium in solution, a structural study of the wild type full-length CA bound to CypA has frustrated attempts by crystallography and NMR spectroscopy. Thus in this investigation we will study the CypA/CA complex using a double mutant CA that exists as a monomer in solution, and retains all the critical properties of the wild type CA including assembly activity. Utilizing 3D/4D-NMR spectroscopy, residual dipolar coupling measurements and biophysical simulations, we will determine the detailed solution structure of the double mutant CA, and of its complex with human CypA. A knowledge of the detailed structure of the CypA/CA complex will provide a structural biology basis in enhancing our understanding of the precise role of CypA within the life cycle of the virus. Such a structure is also likely to contribute to the development of new inhibitors of CypA-CA interaction with therapeutic potential. PUBLIC HEALTH RELEVANCE: This investigation is aimed at the determination of the detailed three dimensional structure of the human Cyclophilin A bound to a mutant capsid protein of HIV-1 virus using a combined solution NMR and biophysical simulation approach.