Kasai Nobuyuki, Mizushina Yoshiyuki, Sugawara Fumio, Sakaguchi Kengo
Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Yamazaki, Noda, Chiba 278-8510.
J Biochem. 2002 Nov;132(5):819-28. doi: 10.1093/oxfordjournals.jbchem.a003292.
Previously, we reported the three-dimensional molecular interactions of nervonic acid (NA) with mammalian DNA polymerase beta (pol beta) [Mizushina et al. (1998) J. Biol. Chem. 274, 25599-25607]. By three-dimensional structural model analysis and comparison with the spatial positioning of specific amino acids binding to NA on pol beta (Leu11, Lys35, His51, and Thr79), we obtained supplementary information that allowed us to build a structural model of human immunodeficiency virus type-1 reverse transcriptase (HIV-1 RT). In HIV-1 RT, Leu100, Lys65, His235, and Thr386 corresponded to these four amino acid residues. These results suggested that the NA binding domains of pol beta and HIV-1 RT are three-dimensionally very similar. The effects of NA on HIV-1 RT are thought to be same as those on pol beta in binding to the rhombus of the four amino acid residues. NA dose-dependently inhibited the HIV-1 RT activity. For binding to pol beta, the kinetics were competitive when the rhombus was present on the DNA binding site. However, as the rhombus in HIV-1 RT was not present in the DNA binding site, the three-dimensional structure of the DNA binding site must be distorted, and subsequently the enzyme is inhibited non-competitively.
此前，我们报道了神经酸（NA）与哺乳动物DNA聚合酶β（polβ）的三维分子相互作用[水嶋等（1998年）。《生物化学杂志》274，25599 - 25607]。通过三维结构模型分析，并与polβ上与NA结合的特定氨基酸（Leu11、Lys35、His51和Thr79）的空间定位进行比较，我们获得了补充信息，这使我们能够构建人类免疫缺陷病毒1型逆转录酶（HIV - 1 RT）的结构模型。在HIV - 1 RT中，Leu100、Lys65、His235和Thr386对应于这四个氨基酸残基。这些结果表明，polβ和HIV - 1 RT的NA结合结构域在三维上非常相似。NA对HIV - 1 RT的作用被认为与对polβ的作用相同，即在与四个氨基酸残基的菱形结合方面。NA剂量依赖性地抑制HIV - 1 RT活性。对于与polβ的结合，当菱形存在于DNA结合位点时，动力学是竞争性的。然而，由于HIV - 1 RT中的菱形不存在于DNA结合位点，DNA结合位点的三维结构必然会扭曲，随后该酶被非竞争性抑制。
