Studies of the fiber to crystal transition of sickle cell hemoglobin in acidic polyethylene glycol.
Studies of the fiber to crystal transition of sickle cell hemoglobin in acidic polyethylene glycol.
复制标题
酸性聚乙二醇中镰状细胞血红蛋白纤维向晶体转变的研究。
DOI：
10.1016/0022-2836(82)90242-x
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发表时间：
1982
影响因子：
5.6
通讯作者：
Josephs,R
中科院分区：
文献类型：
--
作者：
Vassar,RJ;Potel,MJ;Josephs,R
研究了脱氧镰状细胞血红蛋白在酸性（pH 5.2）聚乙二醇（10%）中的结晶，以确定在这种条件下的晶体形成机制是否与在不存在聚乙二醇的情况下在较高pH值下的晶体形成机制具有共同的特征。在不同条件下结晶的共同机制的存在与验证使用已知的高分辨率晶体结构来解释纤维结构有关。我们的研究结果表明，脱氧镰状细胞血红蛋白在酸性聚乙二醇中的结晶是由纤维形成引发的。反过来，纤维在几小时内转化为称为粗纤维的较大结构（Wellemset等人，1981年）。在酸性聚乙二醇中形成的纤维和粗纤维（及其各自的光学变换）似乎具有与在不存在聚乙二醇的情况下在较高pH值下形成的它们的对应物相同的结构。在转变的早期，可以观察到在排列和融合过程中的粗纤维。中间体的结构表征毫无疑问，在酸性聚乙二醇中的结晶是由与在更生理条件下发生的相同的机制介导的，并且纤维是亚稳态中间体，其最终命运是结晶。
The crystallization of deoxygenated sickle cell hemoglobin in acidic (pH 5.2) polyethylene glycol (10%) has been studied in order to determine if the mechanism of crystal formation under such conditions has features in common with the mechanism of crystal formation at higher pH values in the absence of polyethylene glycol. The existence of a common mechanism of crystallization under different conditions is relevant in validating the use of the known high resolution crystal structure to interpret the fiber structure. Our findings indicate that deoxygenated sickle cell hemoglobin crystallization in acidic polyethylene glycol is initiated by fiber formation. Fibers, in turn, convert to larger structures called macrofibers within several hours (Wellemset al., 1981). Fibers and macrofibers (and their respective optical transforms) formed in acidic polyethylene glycol appear to have the same structure as their counterparts formed at higher pH values in the absence of polyethylene glycol. Early in the transition one can observe macrofibers in the process of alignment and fusion. The structural characterization of the intermediates leaves little doubt that crystallization in acidic polyethylene glycol is mediated by the same mechanism as that occurring under more physiological conditions, and that fibers are a metastable intermediate whose ultimate fate is to crystallize.