Structural basis for substrate specificity of single domain APOBEC3s

 描述（由申请方提供）：单结构域APOBEC 3底物特异性的结构基础胞苷脱氨酶APOBEC 3（A3）家族成员提供了抗HIV的第一道防线;然而，HIV通过拮抗A3的病毒感染因子（Vif）逃避A3限制因子。该提案的总体目标是阐明单结构域APOBEC 3底物特异性的结构基础，以了解HIV限制。A3可以通过在逆转录过程中在病毒基因组中引入致命突变来抑制HIV复制。A3酶之间脱氨基ssDNA的底物特异性的差异各不相同，但底物序列特异性的结构基础还没有很好地理解。我假设拓扑和化学差异的活性位点A3酶负责其底物序列特异性。我提出了以下三个目标来验证我的假设：阐明[1] A3与ssDNA亲和力的底物序列依赖性，[2] A3与底物ssDNA相互作用的机制，[3]活性A3 Z结构域活性位点的同源性和特异性之间的相关性。该提案的结果不仅有助于更全面地了解A3功能的结构基础，而且还将为新的创新抗HIV药物开发策略提供重要基础。

 DESCRIPTION (provided by applicant): Structural basis for substrate specificity of single domain APOBEC3s Members of the APOBEC3 (A3) family of cytidine deaminases provide a first line of defense against HIV; however, HIV evades A3 restriction factors through viral infectivity factor (Vif), which antagonizes A3. The overall objective of this proposal is to elucidte the structural basis for substrate specificity of single domain APOBEC3s toward understanding HIV restrictions. A3s can inhibit HIV replication by introducing lethal mutations in the viral genome during reverse transcription. Differences in substrate specificities for deaminating ssDNA among A3 enzymes vary, yet the structural basis for substrate sequence specificity is not well understood. I hypothesize that topological and chemical differences in the active site of A3 enzymes are responsible for their substrate sequence specificities. I propose the following three aims to test my hypothesis: elucidate [1] the substrate sequence dependence of A3 affinity to ssDNA, [2] the mechanism of A3 interaction with substrate ssDNA, and [3] the correlation between homology and specificity of the active site of active A3 Z domains. Results of this proposal will not only contribute to a more comprehensive understanding of the structural basis for A3 function, but will also provide an essential foundation for new innovative anti-HIV drug development strategies.