Elucidating a relationship between conformational sampling and drug resistance in HIV-1 protease.
Elucidating a relationship between conformational sampling and drug resistance in HIV-1 protease.
复制标题
DOI：
10.1021/bi400109d
复制
发表时间：
2013-05-14
期刊：
影响因子：
2.9
通讯作者：
Fanucci GE
中科院分区：
文献类型：
--
作者：
de Vera IM;Smith AN;Dancel MC;Huang X;Dunn BM;Fanucci GE
在快速复制系统中的酶靶点，如逆转录病毒，通常会对药物选择压力做出反应，在活性位点口袋中产生突变，通过引入位阻或消除基本的分子相互作用来限制抑制剂的有效性。然而，这些原始突变倾向于损害致病适应性。新出现的继发性突变，通常在结合腔外发现，可能或可以在保持耐药性的同时恢复适应性。累积的药物压力选择突变可能对耐药性的发展有间接影响，例如改变蛋白质的柔韧性或蛋白质-配体相互作用的动力学。在这里，我们发现耐药变体，D30N/M36I/A71V， HIV-1蛋白酶（HIV-1 PR）的突变积累改变了平衡构象采样集合的分数占用。构象态居群之间是相互关联的；即封闭类、半开放类和开放类，具有抑制常数和动力学参数。稳定封闭构象的突变与酶的活性降低和对抑制剂的亲和力较高相关，这一点在添加抑制剂或底物模拟物后进一步增加了封闭状态的占用率。交叉抗性被发现与突变的组合有关，这些突变以牺牲封闭状态为代价增加了开放样构象的种群，同时保留了半开放种群的原生占位。这些相关性表明，在构象采样模型中，至少需要三种状态才能确定HIV-1 PR中耐药性的出现。更重要的是，这些结果揭示了一种可能的机制，即突变结合在一起，在保持催化活性的同时赋予耐药性。
Enzyme targets in rapidly replicating systems, such as retroviruses, commonly respond to drug-selective pressure with mutations arising in the active site pocket that limit inhibitor effectiveness by introducing steric hindrance or by eliminating essential molecular interactions. However, these primary mutations are disposed to compromising pathogenic fitness. Emerging secondary mutations, which are often found outside of the binding cavity, may or can restore fitness while maintaining drug resistance. The accumulated drug-pressure selected mutations could have an indirect effect in the development of resistance, such as altering protein flexibility or the dynamics of protein-ligand interactions. Here, we show that accumulation of mutations in a drug-resistant variant, D30N/M36I/A71V, HIV-1 protease (HIV-1 PR) changes the fractional occupancy of the equilibrium conformational sampling ensemble. Correlations are made among populations of the conformational states; namely, closed-like, semi-open, and open-like, with inhibition constants, as well as kinetic parameters. Mutations that stabilize a closed-like conformation correlate with enzymes of lowered activity and with higher affinity for inhibitors, which is corroborated by a further increase in the fractional occupancy of the closed state upon addition of inhibitor or substrate-mimic. Cross resistance is found to correlate with combinations of mutations that increase the population of the open-like conformations at the expense of the closed-like state while retaining native-like occupancy of the semi-open population. These correlations suggest that at least three states are required in the conformational sampling model to establish the emergence of drug-resistance in HIV-1 PR. More importantly, these results shed light on a possible mechanism whereby mutations combine to impart drug resistance while maintaining catalytic activity.
登录
查看更多内容
影响因子：
2
作者：
Finiguerra, Michela G.;Prudencio, Miguel;Huber, Martina
通讯作者：
Huber, Martina
影响因子：
2.9
作者：
Clemente, JC;Hemrajani, R;Dunn, BA
通讯作者：
Dunn, BA
影响因子：
5.7
作者：
Ishima, R;Freedberg, DI;Torchia, DA
通讯作者：
Torchia, DA
影响因子：
2.2
作者：
Chiang, YW;Borbat, PP;Freed, JH
通讯作者：
Freed, JH
影响因子：
5.4
作者：
Bandaranayake, Rajintha M.;Kolli, Madhavi;Schiffer, Celia A.
通讯作者：
Schiffer, Celia A.