A computer model for the membrane binding of HIV-1 Gag

描述（由申请人提供）：本研究的总体目标是建立C型逆转录病毒在病毒组装过程中如何与感染细胞的质膜细胞质表面相互作用的计算模型。人类免疫缺陷病毒1型（HIV-1） Gag多蛋白的膜结合需要n端基质（MA）序列中的肉豆酸酯和一簇碱性残基；其他逆转录病毒MAs含有类似的基序。因此，第一个特定的目的是通过使用连续静电模型来计算它们与磷脂双层原子模型的物理相互作用，来验证非特异性静电和疏水相互作用提供足够的能量来解释已知结构的逆转录病毒MAs的膜结合的假设。尽管序列同一性很低，但MAs具有相同的结构褶皱。在每个MA结构中，一簇基本残基位于分子表面，尽管这些残基在线性序列空间中不守恒。因此，在没有序列相似性的情况下，MAs似乎具有结构和静电同源性。第二个具体目标是通过为未知结构的MAs建立模型并计算其生物物理性质来测试这一观察结果的普遍性。为了促进对MA功能的新发现，例如静电相互作用在Gag靶向中发挥一般作用的可能性，第三个具体目标是构建一个结合MAs计算，实验和基因组信息的关系数据库。艾滋病毒需要一个流体膜包膜来保持其结构的完整性，因此，传统的结构技术是不适用的。这一建议为未来逆转录病毒组装和结构的综合计算机模型的计算工作奠定了基础。这项研究是高度创新的，因为它专注于其他方法不容易解决的问题，它将提供对病毒组装至关重要的蛋白质/膜相互作用的分子模型，这可以用来提出新的治疗方法来破坏子代病毒粒子的产生。

DESCRIPTION (provided by applicant): The overall goal of this research is to develop computational models for how type C retroviruses interact with the cytosolic surface of the plasma membrane of infected cells during viral assembly. A myristate and cluster of basic residues in the N-terminal matrix (MA) sequence are required for membrane association of the Gag polyprotein from human immunodeficiency virus type 1 (HIV-1); other retroviral MAs contain similar motifs. Therefore, the first specific aim is to test the hypothesis that nonspecific electrostatic and hydrophobic interactions provide enough energy to account for the membrane binding of retroviral MAs of known structure by using continuum electrostatic models to calculate their physical interactions with atomic models of phospholipid bilayers. MAs share the same structural fold in spite of very low sequence identity. In each MA structure, a cluster of basic residues is located on the surface of the molecule even though these residues are not conserved in linear sequence space. Thus, MAs appear to share structural and electrostatic homology in the absence of sequence similarity. The second specific aim is to test the generality of this observation by building models for MAs of unknown structure and calculating their biophysical properties. In order to facilitate new discoveries about MA function, e.g. the possibility that electrostatic interactions play a general role in Gag targeting, the third specific aim is to construct a relational database which combines computational, experimental and genomic information on MAs. HIV requires a fluid membrane envelope for its structural integrity and is, thus, not amenable to traditional structural techniques. This proposal lays the foundation for future computational work on a comprehensive computer model of retroviral assembly and structure. The research is highly innovative because by focusing on questions that are not easily addressed by other methods, it will provide molecular models of the protein/membrane interactions crucial to viral assembly which can be used to suggest novel therapeutic approaches to disrupting the production of progeny virions.