Loya S, Rudi A, Tal R, Kashman Y, Loya Y, Hizi A
Department of Cell Biology and Histology, Sackler School of Medicine, Tel Aviv, Israel.
Arch Biochem Biophys. 1994 Mar;309(2):315-22. doi: 10.1006/abbi.1994.1119.
The natural product of the Red Sea sponge Verongia sp., identified as 3,5,8-trihydroxy-4-quinolone, was found to be a potent inhibitor of the RNA-directed DNA synthesis of the reverse transcriptases (RTs) of human immunodeficiency viruses type 1 and type 2 (HIV-1 and HIV-2, respectively). This inhibition was unaffected by the nature of the primer template used for DNA synthesis. The DNA-dependent DNA polymerase activity was inhibited to a lesser extent, whereas the ribonuclease H (RNase H) function associated with both HIV RTs was only slightly inhibited. The inhibition by the trihydroxyquinolone is reversible and noncompetitive with respect to both substrates--dTTP and the template primer poly(rA)n.oligo(dT)12-18. The inhibitor binds HIV-1 RT with a high affinity (Ki = 0.46 microM). This compound was shown also to inhibit the catalytic activities of the RT of murine leukemia virus, establishing the general inhibitory effect on retroviral RTs. Introductions of acetyl or methoxy moieties at positions with potential activity have generated three synthetic analogs of the natural compound. Only one analog, 5,8-dimethoxy-4-quinolone, exhibited an inhibition potency similar to that of the unmodified compound. Analysis of the three analogs has led us to the conclusion that the hydroxyl group at the ortho position to the carbonyl group in the pyridinone ring is a key structural element for the inhibitory activity. Thus, it could well be that the inhibitor interacts with the enzyme through a hydrogen bond of this hydroxyl group. We hope that the identification of the inhibitory site of the compound might be an important step toward the rational design of new potent anti-HIV RT drugs.
从红海海绵Verongia sp.中鉴定出的天然产物为3,5,8 - 三羟基 - 4 - 喹诺酮，它被发现是人类免疫缺陷病毒1型和2型（分别为HIV - 1和HIV - 2）逆转录酶（RTs）的RNA指导的DNA合成的有效抑制剂。这种抑制作用不受用于DNA合成的引物模板性质的影响。依赖DNA的DNA聚合酶活性受到的抑制程度较小，而与两种HIV RTs相关的核糖核酸酶H（RNase H）功能仅受到轻微抑制。三羟基喹诺酮的抑制作用是可逆的，并且相对于两种底物——dTTP和模板引物聚（rA）n·寡聚（dT）12 - 18而言是非竞争性的。该抑制剂以高亲和力（Ki = 0.46 microM）结合HIV - 1 RT。还表明该化合物可抑制鼠白血病病毒RT的催化活性，确立了其对逆转录病毒RTs的普遍抑制作用。在具有潜在活性的位置引入乙酰基或甲氧基部分产生了该天然化合物的三种合成类似物。只有一种类似物，即5,8 - 二甲氧基 - 4 - 喹诺酮，表现出与未修饰化合物相似的抑制效力。对这三种类似物的分析使我们得出结论，吡啶酮环中羰基邻位的羟基是抑制活性的关键结构要素。因此很可能该抑制剂通过这个羟基的氢键与酶相互作用。我们希望确定该化合物的抑制位点可能是朝着合理设计新型高效抗HIV RT药物迈出的重要一步。
