THE STRUCTURES OF THE MONOCLINIC AND ORTHORHOMBIC FORMS OF HEN EGG-WHITE LYSOZYME AT 6-A RESOLUTION
THE STRUCTURES OF THE MONOCLINIC AND ORTHORHOMBIC FORMS OF HEN EGG-WHITE LYSOZYME AT 6-A RESOLUTION
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DOI：
10.1107/s0567740882004075
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发表时间：
1982-01-01
期刊：
影响因子：
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通讯作者：
WILSON, KS
中科院分区：
文献类型：
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作者：
ARTYMIUK, PJ;BLAKE, CCF;WILSON, KS
用同构置换法测定了蛋清溶菌酶（HEWL）的单斜和正交结构。在这个分辨率下，分子的构象与HEWL的四边形无法区分。单斜晶型的不对称单元中的两个分子通过近似（a/2+ c/2）的平移关系相连。单晶胞中分子的紧密堆积阻碍了对这种晶体形式进行底物结合研究。在正交晶体中，糖结合位点A和B被阻断，但活性位点间隙的下部似乎是可接近的。因此，这两种晶体形式都不适合在零下温度下结合真正的衬底。
The structures of a monoclinic and an orthorhombic form of hen egg-white lysozyme (HEWL) have been determined at 6A resolution by the method of isomorphous replacement. At this resolution the con-formations of the molecules are indistinguishable from that of the tetragonal form of HEWL. The two molecules in the asymmetric unit of the monoclinic form are related by a translation of approximately (a/2+ c/2). The tight packing of the molecules in the unit cell prevents substrate-binding studies being carried out on this crystal form. In the orthorhombic crystals the sugar-binding sites A and B are blocked but the lower part of the active-site cleft appears to be accessible. Thus, neither of these crystal forms is ideally suited to the binding of true substrate at sub-zero temperatures.