STRUCTURAL ASPECTS OF HEMOGLOBIN S GELATION

本研究建议的目的是为了更好地了解 脱氧血红蛋白S(HBs)参与的分子间接触区 体外聚合，并鉴定其中的官能团 易受化学操纵的区域。到目前为止我们的研究有 证明了HBS的Glu-43(Beta)具有高的羧基选择性 用于碳二亚胺与甘氨酸活化偶联过程中的衍生化反应 乙酯。我们建议继续进行这些研究，以针对 在分子间接触区或附近对羧酸盐的修饰 通过操作胺和/或碳二亚胺组分，并确定 这些衍生化产物对溶解度、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， 一种光活化交联剂，将在特定情况下引入 用羧基研究分子间的拓扑变化 HBS分子经过成核和成核时的接触区 生长阶段形成凝胶。金刚烷基的反应性 将对苯乙醛的HBS进行研究，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醛 学习。潜在的交联性的潜在用处 乙醇醛和α-羟基丙酮在分子间鉴定中的应用 脱氧HBS在成核和生长阶段的接触区 将会被调查。其最终目标是理解 脱氧HBS分子间接触区的相互作用 凝胶作用，我们已经启动的片段互补研究将 待续。α-的共价类似物的制备方法 并将开发Betas链。具有化学突变的新型混合HBs 在两个或更多所需地点将准备研究 聚合过程中的各种分子间接触区。结果是 这些研究将有助于更好地理解一种)化学物质 羧基和胍基在分子间接触上的反应性 区域和b)各种分子间接触的相对贡献 体外聚合的成核和生长阶段的区域。 关于脱氧聚合的结构方面的详细知识 HBS预计将导致针对以下目标的新的特定试剂的设计 特定的分子间接触区域。这样的试剂会 中和β-6位突变对聚合的影响 可能为设计新的抗呕吐剂铺平道路。

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.