A structural and thermodynamic escape mechanism from a drug resistant mutation of the HIV-1 protease
A structural and thermodynamic escape mechanism from a drug resistant mutation of the HIV-1 protease
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DOI：
10.1002/prot.20069
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发表时间：
2004-05-15
影响因子：
2.9
通讯作者：
Freire, E
中科院分区：
文献类型：
--
作者：
Vega, S;Kang, LW;Freire, E
HIV-1蛋白酶抑制疗法的功效通常受到蛋白酶分子中出现突变的影响，这些突变降低了抑制剂的结合亲和力，同时保持了可行的催化活性和底物亲和力。V82 F/I84 V双突变位于结合位点空腔内，影响临床使用的所有蛋白酶抑制剂。KNI-764是目前正在开发的第二代抑制剂，通过熵补偿亲合力损失，从而最大限度地减少结合亲和力的损失，从而保持对这种突变的显著效力。KNI-577与ENI-764的不同之处在于对蛋白酶突变的抑制剂反应至关重要的单一官能团。这一单一差异将两种抑制剂对突变的反应改变一个数量级。因此，对抑制剂反应的结构理解将为设计对传递耐药性的突变不太敏感的抑制剂提供重要指导。与野生型和V82 F/I84 V HIV-1蛋白酶结合的两种化合物的结构已通过X射线晶体学在2.0埃分辨率下确定。通过可旋转键连接到抑制剂支架的两个不对称官能团的存在允许KNI-764比具有单个不对称基团的KNI-577更容易适应突变的结合位点腔。当面对耐药突变蛋白酶时，两种抑制剂的结合焓损失约2.5 kcal/mol;然而，ENI-764获得结合熵，而ENI-577失去结合熵。ENI-764结合熵的增加解释了其对耐药突变的低敏感性。当KNI-764与突变蛋白酶结合时，与结合相关的热容量变化变得更负，与增加的去溶剂化一致。使用KNI-577，观察到相反的效果。在结构上，当ENI-764与耐药突变体结合时，ENI-764的晶体学B因子增加。KNI-577的情况则相反。与这些观察结果一致，KNI-764似乎能够获得。结合熵通过双重机制：它通过将自身更深地埋在结合口袋中获得溶剂化熵，并且通过失去与蛋白酶的相互作用获得构象熵。(C)2004 Wiley-Liss，Inc.
The efficacy of HIV-1 protease inhibition therapies is often compromised by the appearance of mutations in the protease molecule that lower the binding affinity of inhibitors while maintaining viable catalytic activity and substrate affinity. The V82F/I84V double mutation is located within the binding site cavity and affects all protease inhibitors in clinical use. KNI-764, a second-generation inhibitor currently under development, maintains significant potency against this mutation by entropically compensating for enthalpic losses, thus minimizing the loss in binding affinity. KNI-577 differs from ENI-764 by a single functional group critical to the inhibitor response to the protease mutation. This single difference changes the response of the two inhibitors to the mutation by one order of magnitude. Accordingly, a structural understanding of the inhibitor response will provide important guidelines for the design of inhibitors that are less susceptible to mutations conveying drug resistance. The structures of the two compounds bound to the wild type and V82F/I84V HIV-1 protease have been determined by X-ray crystallography at 2.0 Angstrom resolution. The presence of two asymmetric functional groups, linked by rotatable bonds to the inhibitor scaffold, allows KNI-764 to adapt to the mutated binding site cavity more readily than KNI-577, with a single asymmetric group. Both inhibitors lose about 2.5 kcal/mol in binding enthalpy when facing the drug-resistant mutant protease; however ENI-764 gains binding entropy while ENI-577 loses binding entropy. The gain in binding entropy by ENI-764 accounts for its low susceptibility to the drug-resistant mutation. The heat capacity change associated with binding becomes more negative when KNI-764 binds to the mutant protease, consistent with increased desolvation. With KNI-577, the opposite effect is observed. Structurally, the crystallographic B factors increase for ENI-764 when it is bound to the drug-resistant mutant. The opposite is observed for KNI-577. Consistent with these observations, it appears that KNI-764 is able to gain. binding entropy by a two-fold mechanism: it gains solvation entropy by burying itself deeper within the binding pocket and gains conformational entropy by losing interaction with the protease. (C) 2004 Wiley-Liss, Inc.