study of the HIV integrase catalytic core domain and inhibitor binding

通过大量的突变试验和错误的努力，已经产生了稳定的HIV1整合酶催化核心区的同源二聚体结构。尽管在非常类似于生理环境的条件下，该酶快速采样不同的构象状态，导致广泛的谱线加宽和核磁共振信号的消失，但我们发现了包括高镁浓度(40 MM)的条件，其中平衡移动到似乎是一个主要状态和一个次要状态，这在C-末端螺旋的结构上彼此不同。对弛豫数据的分析提供了对活动站点的动力学特性的洞察，它确实显示了相当大的幅度的高频运动，但显示了该站点之前的螺旋的连续性，远远超出了在许多X射线结构中所看到的。

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.