study of the HIV integrase catalytic core domain and inhibitor binding

通过广泛的诱变试验和错误的努力，已经产生了一个稳定的、同型二聚体的HIV1整合酶催化核心结构域。尽管在与生理环境非常相似的条件下，酶快速采样不同的构象状态，导致谱线广泛拓宽和核磁共振信号消失，但我们发现，在高Mg2+浓度（40 mM）的条件下，平衡转移到似乎是一个主要和一个次要的状态，这在c端螺旋的结构中彼此不同。对弛豫数据的分析提供了对活性位点动态特性的深入了解，它确实显示出相当大的振幅高频运动，但显示出螺旋在该位点之前的延续，远远超出了许多x射线结构所看到的。

Through extensive mutagenesis trial-and-error efforts, a stable, homodimeric construct of the catalytic core domain of the HIV1 integrase enzyme has been generated. Although under conditions that closely resemble the physiological environment the enzyme rapidly samples different conformational states, leading to extensive line broadening and disappearance of NMR signals, we have found conditions that include high Mg2+ concentrations (40 mM) where the equilibrium is shifted to what appear to be one major and one minor state, that differ from one another in the structure of the C-terminal helix. Analysis of relaxation data provides insights into the dynamic properties of the active site, which indeed shows considerable amplitude high frequency motions, but shows a continuation of the helix preceding this site well beyond what is seen in many X-ray structures.