STRUCTURAL ASPECTS OF HEMOGLOBIN S GELATION

本研究建议的目的是更好地了解 脱氧血红蛋白S（HbS）的分子间接触区域参与了 在体外聚合，并确定在这些官能团 适合化学操作的区域。 迄今为止，我们的研究 证明了HbS的Glu-43（Beta）的羧基的高选择性 用于在碳二亚胺活化的与甘氨酸偶联期间的衍生化 乙基酯。 我们建议继续进行这些研究， 在分子间接触区或其附近对羧酸盐的改性 通过操纵胺和/或碳二亚胺组分，并测定 这些衍生化对溶解度、延迟时间等的影响 HbS的功能特性。 N-（β-氨基乙基）4-叠氮基-2-硝基苯胺， 一种可光活化的交联剂，将被引入到具体的 羧基，以研究分子间的拓扑变化 当HbS分子通过成核和接触区域时， 生长阶段形成凝胶。 的胍基基团的反应性， 将研究HbS对苯乙二醛的反应，目的是介绍 用于化学交联的特定精氨酸残基上的叠氮苯乙二醛 问题研究 的潜在交联性质的潜在有用性， 乙醇醛和α-羟基丙酮在分子间识别中的应用 脱氧HbS的接触区参与成核和生长阶段 将被调查。 最终目的是了解 脱氧HbS分子间接触区的相互作用键 凝胶化，我们已经开始的片段互补研究将 请继续。 用于制备α-羟基喹啉的共价类似物的程序 Betas连锁店将被开发出来。 具有化学突变的新杂交HbS 在两个或两个以上所需的网站将准备研究的协同性， 聚合过程中的各种分子间接触区域。 结果 这些研究将导致更好地了解a）化学 羧基和胍基在分子间接触时的反应性 区域和B）各种分子间接触的相对贡献 在体外聚合的成核和生长阶段的区域。 脱氧聚合的结构方面的详细知识 HbS有望导致设计新的、特异性的试剂， 特定的分子间接触区域。 这种试剂， 中和β-6位突变的聚合影响 可为设计新的防粘剂铺平道路。

The aim of the present research proposal is to better understand the intermolecular contact regions of deoxyhemoglobin S (HbS) involved in the in vitro polymerization and to identify the functional groups in these regions amenable for chemical manipulation. Our studies to date have demonstrated the high selectivity of carboxyl groups of Glu-43(Beta) of HbS for derivatization during the carbodiimide activated coupling with glycine ethyl ester. We propose to continue these studies to target the modification to carboxylates at or near the intermolecular contact regions by manipulating the amine and/or carbodiimide components, and determine the influence of these derivatizations on the solubility, delay time, and other functional properties of HbS. N-(Beta-aminoethyl) 4-azido-2 nitroaniline, a photoactivable cross-linking reagent, will be introduced on specific carboxyl groups to study the topological changes around the intermolecular contact regions as the HbS molecule goes through the nucleation and the growth phases to form the gel. The reactivity of the guanidino groups of HbS toward phenylglyoxal will be studied, with the objective of introducing azidophenylglyoxal on specific arginine residue for chemical cross-linking studies. The potential usefulness of the latent cross-linking nature of glycolaldehyde and Alpha-hydroxy acetone in identifying the intermolecular contact regions of deoxy HbS involved in the nucleation and growth phases will be investigated. With the ultimate objective of understanding the interaction linkage of intermolecular contact regions of deoxy HbS during gelation, the fragment complementation studies that we have initiated will be continued. Procedures for the preparation of covalent analogs of Alpha- and Betas chains will be developed. New hybrid HbS with chemical mutations at two or more desired sites will be prepared to study the cooperativity of various intermolecular contact regions during polymerization. The results of these studies will lead to a better understanding of a) chemical reactivity of carboxyl and guanidino groups at the intermolecular contact regions and b) relative contribution of various intermolecular contact regions in the nucleation and growth phases of in vitro polymerization. The detailed knowledge of the structural aspects of polymerization of deoxy HbS is expected to lead to the design of new, specific reagents targeted to specific intermolecular contact regions. Such reagents that would neutralize the polymerizing influence of the mutation at Beta-6 position could pave the way for designing new antisickling agents.