CRYSTAL-STRUCTURE OF SICKLE-CELL DEOXYHEMOGLOBIN AT 5 A RESOLUTION
CRYSTAL-STRUCTURE OF SICKLE-CELL DEOXYHEMOGLOBIN AT 5 A RESOLUTION
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DOI：
10.1016/s0022-2836(75)80108-2
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发表时间：
1975-01-01
影响因子：
5.6
通讯作者：
LOVE, WE
中科院分区：
文献类型：
--
作者：
WISHNER, BC;WARD, KB;LOVE, WE
镰状细胞脱氧血红蛋白的晶体从含有聚乙二醇和柠檬酸盐-磷酸盐缓冲液的溶液中生长，pH在5和6之间。晶体属单斜晶系，空间群P21，a =63·28 °，B=184·19 °，c=52·84 °，β=92·67°。通过旋转和平移搜索程序确定结构。结构振幅和相位计算从脱氧Hb§ A分子的原子坐标适当地定位在脱氧Hb S晶体的晶胞中。在5 μ m分辨率下计算了Hb S晶体的AnFo−Fodifference Fourier，在pH 7的聚乙二醇溶液中，Hb S分子靠近Val 6 β残基的部分与脱氧Hb A分子结晶的相同部分似乎没有显著差异。在Hb S晶体中，分子轴与晶轴夹角小于10°。分子排列成成对的互锁链，并与轴对齐。每一对中的两股股大约有一个2倍的螺旋轴在它们之间纵向延伸。每对链内的分子间接触涉及Val 6 β和被认为影响镰状化相互作用的其他残基。双链，类似于那些在Hb S晶体中发现的，可以被纳入到一个纤维模型，这是符合现有的信息脱氧Hb S纤维的结构在体内。
Crystals of sickle-cell deoxyhemoglobin were grown from solutions containing polyethylene glycol and citrate-phosphate buffer at a pH between 5 and 6. The crystals have the symmetry of the monoclinic space groupP21, witha=63·28 Å,b=184·19 Å,c=52·84 Å, andβ=92·67°. The structure was determined by rotational and translational search procedures. Structure amplitudes and phases were calculated from the atomic co-ordinates of deoxy Hb§ A molecules appropriately positioned in the unit cell of the deoxy Hb S crystal. AnFo−Fodifference Fourier for the Hb S cristal was compouted at 5 Å resolution.Portions of the Hb S molecules near the Val6β residues do not appear to be significantly different from the same portions of deoxy Hb A molecules crystallized in polyethylene glycol solutions at pH 7. In the Hb S crystal the molecularxaxes enclose angle of less than 10° with the crystallographicaaxis. The molecules are arranged in pairs of interlocking strands aligned with theaaxis. The two strands in each pair are related approximately a 2-fold screw axis running between them longitudinally. Intermolecular contacts within each pair of strands involve Val6β and other residues that are believed to affect sickling interactions. Double strands, similar to those found in the Hb S crystal, can be incorporated into a fiber model that is consistent with available information on the structure of deoxy Hb S fibersin vivo.