Liu Fengling, Kovalevsky Andrey Y, Louis John M, Boross Peter I, Wang Yuan-Fang, Harrison Robert W, Weber Irene T
Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, GA 30303, USA.
J Mol Biol. 2006 May 19;358(5):1191-9. doi: 10.1016/j.jmb.2006.02.076. Epub 2006 Mar 20.
Mutations in HIV-1 protease (PR) that produce resistance to antiviral PR inhibitors are a major problem in AIDS therapy. The mutation F53L arising from antiretroviral therapy was introduced into the flexible flap region of the wild-type PR to study its effect and potential role in developing drug resistance. Compared to wild-type PR, PR(F53L) showed lower (15%) catalytic efficiency, 20-fold weaker inhibition by the clinical drug indinavir, and reduced dimer stability, while the inhibition constants of two peptide analog inhibitors were slightly lower than those for PR. The crystal structure of PR(F53L) was determined in the unliganded form at 1.35 Angstrom resolution in space group P4(1)2(1)2. The tips of the flaps in PR(F53L) had a wider separation than in unliganded wild-type PR, probably due to the absence of hydrophobic interactions of the side-chains of Phe53 and Ile50'. The changes in interactions between the flaps agreed with the reduced stability of PR(F53L) relative to wild-type PR. The altered flap interactions in the unliganded form of PR(F53L) suggest a distinct mechanism for drug resistance, which has not been observed in other common drug-resistant mutants.
导致对抗病毒蛋白酶抑制剂产生耐药性的HIV-1蛋白酶（PR）突变是艾滋病治疗中的一个主要问题。将抗逆转录病毒治疗产生的F53L突变引入野生型PR的柔性侧翼区域，以研究其在耐药性产生中的作用和潜在机制。与野生型PR相比，PR(F53L)的催化效率较低（低15%），对临床药物茚地那韦的抑制作用弱20倍，二聚体稳定性降低，而两种肽模拟抑制剂的抑制常数略低于PR。PR(F53L)的晶体结构在空间群P4(1)2(1)2中以1.35埃分辨率的无配体形式确定。PR(F53L)侧翼的尖端间距比无配体野生型PR更宽，这可能是由于Phe53和Ile50'侧链的疏水相互作用缺失。侧翼之间相互作用的变化与PR(F53L)相对于野生型PR稳定性降低一致。PR(F53L)无配体形式中侧翼相互作用的改变提示了一种独特的耐药机制，这在其他常见的耐药突变体中尚未观察到。
