Andreola M L, Nevinsky G A, Barr P J, Sarih-Cottin L, Bordier B, Fournier M, Litvak S, Tarrago-Litvak L
Institut de Biochemie Cellulaire et Neurochimie du Centre National de la Recherche Scientifique, Bordeaux, France.
J Biol Chem. 1992 Sep 25;267(27):19356-62.
The precursor homodimeric p66/p66 form of human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT) possesses the DNA polymerase and RNase H activities involved in the synthesis of the double-stranded provirus DNA. Reverse transcription is initiated from tRNALys in the case of HIV-1. The present study confirmed that interactions between HIV-1 RT and tRNALys induce protein conformational changes and demonstrated that these interactions stimulate the enzymatic activities associated with the p66 subunit. Thus, the p66/p66 form of the enzyme is strongly stimulated in both DNA polymerase and RNase H activities. Preincubation of the enzyme with tRNA is an obligatory step to obtain the stimulatory effect. The affinity of template, primer, or substrate for RT p66/p66 did not change when the enzyme was preincubated with tRNALys at stimulatory concentrations; the interaction of tRNA with p66/p66 has an effect only on the maximal rate of polymerization. It is further shown that the RNase H domain of RT is much more accessible to protease attack than the DNA polymerase active site.
人类免疫缺陷病毒1型逆转录酶（HIV-1 RT）的前体同源二聚体p66/p66形式具有参与双链前病毒DNA合成的DNA聚合酶和核糖核酸酶H活性。对于HIV-1而言，逆转录从赖氨酸转运RNA（tRNALys）开始。本研究证实，HIV-1 RT与tRNALys之间的相互作用会诱导蛋白质构象变化，并表明这些相互作用会刺激与p66亚基相关的酶活性。因此，该酶的p66/p66形式在DNA聚合酶和核糖核酸酶H活性方面均受到强烈刺激。将该酶与tRNA预孵育是获得刺激效果的必要步骤。当该酶与处于刺激浓度的tRNALys预孵育时，模板、引物或底物对RT p66/p66的亲和力并未改变；tRNA与p66/p66的相互作用仅对聚合的最大速率有影响。进一步表明，RT的核糖核酸酶H结构域比DNA聚合酶活性位点更容易受到蛋白酶攻击。
