Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, United States.
Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, United States.
J Mol Biol. 2018 Jun 22;430(13):1891-1900. doi: 10.1016/j.jmb.2018.02.027. Epub 2018 May 8.
The mature HIV-1 reverse transcriptase is a heterodimer that comprises 66 kDa (p66) and 51 kDa (p51) subunits. The latter is formed by HIV-1 protease-catalyzed removal of a C-terminal ribonuclease H domain from a p66 subunit. This proteolytic processing is a critical step in virus maturation and essential for viral infectivity. Here, we report that tRNA significantly enhances in vitro processing even at a substoichiometric tRNA:p66/p66 ratio. Other double-stranded RNAs have considerably less pronounced effect. Our data support a model where interaction of p66/p66 with tRNA introduces conformational asymmetry in the two subunits, permitting specific proteolytic processing of one p66 to provide the mature RT p66/p51 heterodimer.
成熟的 HIV-1 逆转录酶是一种由 66kDa(p66)和 51kDa(p51)亚基组成的异二聚体。后者是由 HIV-1 蛋白酶催化从 p66 亚基中切除 C 末端核糖核酸酶 H 结构域形成的。这种蛋白水解加工是病毒成熟的关键步骤,对病毒感染力至关重要。在这里,我们报告说,tRNA 即使在亚化学计量的 tRNA:p66/p66 比下,也能显著增强体外加工。其他双链 RNA 的影响要小得多。我们的数据支持这样一种模型,即 p66/p66 与 tRNA 的相互作用在两个亚基中引入构象不对称性,允许对一个 p66 进行特异性蛋白水解加工,从而提供成熟的 RT p66/p51 异二聚体。