Hare Stephen, Cherepanov Peter, Wang Jimin
Division of Medicine, St Mary's Campus, Imperial College London, Norfolk Place, London, UK.
Acta Crystallogr D Biol Crystallogr. 2009 Sep;65(Pt 9):966-73. doi: 10.1107/S0907444909023695. Epub 2009 Aug 14.
The symmetry inherent to many biological macromolecular assemblies has been implicated in a range of crystal pathologies, including lattice-translocation defects (LTDs). Crystals suffering from classic LTDs contain two lattices that are shifted with respect to each other but nonetheless remain within the length of coherent interference. LTD introduces an undesirable intensity modulation into diffraction data, resulting in scrambled or partially scrambled electron densities. In this report, LTD theory is extended and a new general method for determining defect fractions is developed based on the heights of the non-origin peaks observed in native Patterson maps. The application of this method to crystals of lentiviral integrase in complex with its cofactor, where the observed translocation vector does not equal a small integral fraction of a unit-cell edge, is reported and its general application to all classic LTD cases is predicted.
许多生物大分子组装体固有的对称性与一系列晶体病理学现象有关，包括晶格移位缺陷（LTDs）。患有典型LTDs的晶体包含两个彼此相对移位但仍处于相干干涉长度范围内的晶格。LTD会在衍射数据中引入不良的强度调制，导致电子密度混乱或部分混乱。在本报告中，LTD理论得到了扩展，并基于在原生帕特森图中观察到的非原点峰的高度，开发了一种确定缺陷分数的新通用方法。本文报道了该方法在慢病毒整合酶与其辅因子复合物晶体中的应用，其中观察到的移位向量不等于单位晶胞边缘的小整数分数，并预测了其在所有经典LTD案例中的普遍应用。
