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BAND 3 N-TERMINAL AA (10-16) AND DEOXY S POLYMERIZATION

带 3 N 端 AA (10-16) 和脱氧 S 聚合

基本信息

批准号：
3353261
负责人：
JOHN W HARRIS
金额：
$ 9.55万
依托单位：
CASE WESTERN RESERVE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1988
资助国家：
美国
起止时间：
1988-02-01 至 1992-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/3353261
关键词：
chemical binding chemical structure function conformation gel electrophoresis hemoglobin Ss polymerization protein sequence sickle cell anemia synthetic peptide

项目摘要

The polymerization and sol-gel transformation of deoxyhemoglobin S will be inhibited by an unexplored mechanism in which the close approach of hemoglobin molecules necessary to initiate and propagate polymerization is prevented and the hemoglobin is allowed to remain fully functional. Peptides of the amino acid sequence present in the N-terminal portion of Band 3 of the human erythrocyte bind reversibly to hemoglobin A at the 2,3-DPG receptor locus. Binding to the deoxy conformation is much greater than to the oxy. The peptides extend deep into the cavity between the beta chains and, depending on length, protrude for varying distances beyond the confines of the tetrad. The interactions between fragments of the N-terminal cytoplasmic portion of Band 3 and hemoglobin S are comparable with those of hemoglobin A but the effect of such peptides on the polymerization of deoxy S has not been explored. It is postulated that 1) a 15 amino acid peptide of the same sequences as in the N-terminal cytoplasmic domain of Band 3 will enter the inter-betaS chain region a distance of 18 angstrom and protrude approximately 27 angstrom outside the molecule to occupy and occlude a hemispheric volume of 27 angstrom radius around the 2,3-DPG binding site of the betaS chains and 2) the protruding portion of the peptide will, by sheer bulk or by covering up specific interacting sites, prevent the 1-5 angstrom approaches that the surface beta 6 mutant and other contact areas must make to initiate polymerization. Additional steric impedance to hemoglobin S polymer formation may arise from 1) disordering of the beta chains in the 10-12 residues f the C-termini and in the 3 N-terminal amino acids before the A helix (Changes induced in hemoglobin A by the peptide), and 3) the formation of binary complexes of deoxyhemoglobin S molecules tethered together by the peptide in beta-to-beta chain apposition. These could not properly incorporate into the polymer. The peptides will be designed, synthesized, purified, and characterized: evaluation of reactions with hemoglobin will be by Csat, time-viscosity profile, physical properties of gel, P50, competitive binding with other polyanions, change in charge and M.W. The binding, reversibility, and steric interference will be optimized by varying the molar rations of peptide to hemoglobin, peptide length, amino acid sequence, an contour. Results will provide new data on nucleation, the polymerization reaction, and the structure of polymer and gel. A new class of inhibitors will be defined that may ultimately find applicability in controlling the intracellular polymerization basic to the pathophysiology and clinical manifestations of sickle cell disorders.

脱氧血红蛋白的聚合和溶胶-凝胶转化 S将被一种未知的机制抑制，在这种机制下，启动和启动所需的血红蛋白分子的探讨防止了增殖聚合，并允许使用血红蛋白才能保持完整的功能。氨基酸序列中的多肽存在于人类条带3的N-末端部分红细胞与2，3-DPG受体上的血红蛋白A可逆结合轨迹。与脱氧构象的结合比与脱氧构象的结合大得多奥克西林。多肽深入到贝塔之间的空腔中链条，并根据长度的不同突出不同的距离超越了四分体的界限。两国之间的相互作用带3和带3 N端细胞质部分的片段血红蛋白S与血红蛋白A相当，但这些多肽对脱氧S的聚合没有影响已经被探索过了。据推测，1)一个15个氨基酸的多肽与N端胞质结构域相同的序列带3将进入Betas间链区，距离为18 埃斯特罗姆，凸出约27埃分子占据和遮挡27埃的半球体积围绕Betas链的2，3-DPG结合部位的半径和2) 多肽的突出部分将以纯粹的体积或通过掩盖特定的相互作用部位，防止1-5埃表面β6突变体和其他接触区域的途径必须制造才能引发聚合。附加空间阻抗对血红蛋白S聚合体的形成可能有1)无序 C-末端10-12个残基中的β链和 A螺旋前的3个N-末端氨基酸(在血红蛋白A)，以及3)二元组分的形成脱氧血红蛋白S分子的络合物 β-β链上的多肽。这些都不能正确地加入到聚合物中。这些多肽将被设计出来，合成、提纯和表征：反应评估与血红蛋白将通过Csat，时间-粘度分布，物理凝胶的性质，P50，与其他聚阴离子的竞争结合，电荷变化与M.W.结合、可逆性和立体通过改变摩尔比来优化干涉肽到血红蛋白、肽长度、氨基酸序列和等高线。结果将提供关于成核的新数据，聚合反应，以及聚合物和凝胶的结构。一个将定义一类新的抑制剂，最终可能会发现在控制胞内聚合基础上的适用性对镰状细胞的病理生理和临床表现的影响精神错乱。