STRUCTURE OF BACTERIOPHAGE-T4 LYSOZYME REFINED AT 1.7 A RESOLUTION
STRUCTURE OF BACTERIOPHAGE-T4 LYSOZYME REFINED AT 1.7 A RESOLUTION
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DOI：
10.1016/0022-2836(87)90636-x
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发表时间：
1987-01-05
影响因子：
5.6
通讯作者：
MATTHEWS, BW
中科院分区：
文献类型：
--
作者：
WEAVER, LH;MATTHEWS, BW
来自噬菌体T4的溶菌酶的结构已在1.7埃分辨率下精修至19.3%的晶体学残差。最终模型的键长和键角与“理想”值分别相差0.019埃和2.7度。晶体从电子密度高的磷酸盐溶液中生长，使用适当的溶剂连续体显著改善了低分辨率下观测到的和计算出的结构因子之间的一致性。除了一些侧链构象的变化外，精修确认了该分子最初从2.4埃分辨率电子密度图得出的结构。晶体中有118个排列有序的溶剂分子与T4溶菌酶分子相关联。其中4个或多或少是被掩埋的。在活性位点裂隙内有水分子的聚集，但除此之外，溶剂分子分散在分子表面周围，不会聚集成冰状结构或五边形或六边形簇。晶体中T4溶菌酶的明显运动可以用对应于活性位点裂隙打开和关闭的显著结构域间运动来解释。对于氨基末端结构域，该运动可以同样好地（相关系数约为0.87）描述为围绕一个点或一个旋转轴的准刚体运动。羧基末端结构域在晶体中的运动最好描述为围绕一个轴的旋转（相关系数0.80），尽管在这种情况下，明显的运动似乎部分受到晶体接触的影响，并且对于溶液中的动力学可能相关性存疑。
The structure of the lysozyme from bacteriophage T4 has been refined at 1.7 .ANG. resolution to a crystallographic residual of 19.3%. The final model has bond lengths and bond angles that differ from "ideal" values by 0.019 .ANG. and 2.7.degree., respectively. The crystals are grown from electron-dense phosphate solutions and the use of an appropriate solvent continuum substantially improved the agreement between the observed and calculated structure factors at low resolution. Apart from changes in the conformations of some side-chains, the refinement confirms the structure of the molecule as initially derived from a 2.4 .ANG. resolution electron density map. There are 118 well-ordered solvent molecules that are associated with the T4 lysozyme molecule in the crystal. Four of these are more-or-less buried. There is a clustering of water molecules within the active site cleft but, other than this, the solvent molecules are dispersed around the surface of the molecule and do not aggregate into ice-like structures or pentagonal or hexagonal clusters. The apparent motion of T4 lysozyme in the crystal can be interpreted in terms of significant interdomain motion corresponding to an opening and closing of the active site cleft. For the amino-terminal domain the motion can be described equally well (correlation coefficients approx. 0.87) as quasi-rigid-body motion either about a point or about an axis of rotation. The motion in the crystals of the carboxy-terminal domain is best described as rotation about an axis (correlation coefficient 0.80) although in this case the apparent motion seems to be influenced in part by crystal contacts and may be of questionable relevance to dynamics in solution.