Crystal structure of an in vivo HIV-1 protease mutant in complex with saquinavir: Insights into the mechanisms of drug resistance
Crystal structure of an in vivo HIV-1 protease mutant in complex with saquinavir: Insights into the mechanisms of drug resistance
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DOI：
10.1110/ps.9.10.1898
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发表时间：
2000-10-01
期刊：
影响因子：
8
通讯作者：
Tang, J
中科院分区：
文献类型：
--
作者：
Hong, L;Zhang, XJC;Tang, J
沙奎那韦是一种广泛应用于艾滋病治疗的HIV-1蛋白酶抑制剂药物。然而，它的有效性受到了耐药突变的阻碍，这是针对HIV-1病毒酶的抑制剂药物的常见问题。三种HIV-1蛋白酶突变体种类，G48 V、L90 M和G48 V/L90 M双突变体，在体内通过酶与沙奎那韦抗性相关（Jacobsen等人，1996年）。对这些突变体的动力学研究表明，与野生型酶相比，Ki值分别增加了13.5倍、3倍和419倍（Ermolieff J，Lin X，Tang. J，1997，Biochemistry 36：12364-12370）。为了理解这些突变如何调节抑制剂结合，我们已经在2.6埃分辨率下解析了与沙奎那韦复合的G48 V/L90 M双突变体的HIV-I蛋白酶晶体结构。将该突变体复合物与结合相同抑制剂的野生型酶的复合物进行比较（克罗恩A、雷德肖S、里奇JC、格雷夫斯BJ、波多田MH，1991，J Med Chern 34：3340-3342）。我们的分析表明，以适应在位置48的缬氨酸侧链，抑制剂移动远离蛋白酶，导致在抑制剂P3亚位点和酶的午睡区域之间形成更大的间隙。其他亚位点也表明抑制剂相互作用减少，由于抑制剂构象的整体变化。在位置90处的新的甲硫氨酸侧链与活性位点残基的主链原子具有货车范德华相互作用，导致S1/S1'底物结合口袋的体积和结构灵活性降低。突变体甲硫氨酸侧链与底物易裂键或抑制剂的电子等排体部分之间的间接相互作用可能不同于野生型酶的那些，因此可能促进抗性突变体的催化作用。
Saquinavir is a widely used HIV-1 protease inhibitor drug for AIDS therapy. Its effectiveness, however, has been hindered by the emergence of resistant mutations, a common problem for inhibitor drugs that target HIV-1 viral enzymes. Three HIV-1 protease mutant species, G48V, L90M, and G48V/L90M double mutant, are associated in vivo with saquinavir resistance by the enzyme (Jacobsen et al., 1996). Kinetic studies on these mutants demonstrate a 13.5-, 3-, and 419-fold increase in K-i values, respectively, compared to the wild-type enzyme (Ermolieff J, Lin X, Tang. J, 1997, Biochemistry 36:12364-12370). To gain an understanding of how these mutations modulate inhibitor binding, we have solved the HIV-I protease crystal structure of the G48V/L90M double mutant in complex with saquinavir at 2.6 Angstrom resolution. This mutant complex is compared with that of the wild-type enzyme bound to the same inhibitor (Krohn A, Redshaw S, Richie JC, Graves BJ, Hatada MH, 1991, J Med Chern 34:3340-3342). Our analysis shows that to accommodate a valine side chain at position 48, the inhibitor moves away from the protease, resulting in the formation of larger gaps between the inhibitor P3 subsite and the nap region of the enzyme. Other subsites also demonstrate reduced inhibitor interaction due to an overall change of inhibitor conformation. The new methionine side chain at position 90 has van der Waals interactions with main-chain atoms of the active site residues resulting in a decrease in the volume and the structural flexibility of S1/S1' substrate binding pockets. Indirect interactions between the mutant methionine side chain and the substrate scissile bond or the isostere part of the inhibitor may differ from those of the wild-type enzyme and therefore may facilitate catalysis by the resistant mutant.