Studies of molecular crowding

分子拥挤的研究

• 批准号: 8741360
• 负责人: Allen P Minton
• 金额: $ 20.29万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8741360
• 关键词: Affinity; Amines; Behavior; Binding; Biological; Complex; Crowding; Dependence; Elements; Fluorescence; Goals; Individual; Label; Liquid substance; Measurement; Methods; Modeling; Molecular; Oxides; Relaxation; Site; Soybeans; Sum; System; Thermodynamics; Time; Titrations; Trypsin Inhibitors; Urea; Work; base; chymotrypsin; chymotrypsin A; macromolecule; theories

1. The effect of urea and trimethyl-N-amine oxide (TMAO) upon the heteroassociation of alpha-chymotrypsin (chy) and soybean trypsin inhibitor (STI) was studied by measurement of fluorescence depolarization. STI was labeled with Alexa-488 and titrated with chy. The dependence of the rotational relaxation time of labeled STI upon the concentration of added chy was interpreted in the context of a model in which chy could bind to two independent sites on STI with approximately equal affinity. Titrations were conducted in the presence of various added concentrations of urea and TMAO, and it was found that while added urea tended to inhibit the association of chy and STI, TMAO enhanced the association. Analysis of the dependence of results upon the concentrations of added urea and TMAO showed that the two effects, although in opposite directions, were additive. (D. Wu) 2. The overall effect of a concentrated crowding agent upon a model for self-association of a dilute reactant was analyzed as the sum of the effects of both excluded volume and attractive interactions between the crowding agent and the reactant species. (A. Minton)

1.通过荧光去极化的测量，研究了尿素和三甲基氧化胺（TMAO）对α-胰凝乳蛋白酶（chy）和大豆胰蛋白酶抑制剂（STI）杂结合的影响。 STI 用 Alexa-488 标记并用 chy 滴定。 标记的 STI 的旋转弛豫时间对添加的 chy 浓度的依赖性在模型中进行了解释，其中 chy 可以以大致相等的亲和力结合到 STI 上的两个独立位点。 在添加不同浓度的尿素和 TMAO 的情况下进行滴定，结果发现，虽然添加的尿素倾向于抑制 chy 和 STI 的关联，但 TMAO 却增强了这种关联。 对结果对添加尿素和TMAO浓度的依赖性的分析表明，这两种效应虽然方向相反，但却是相加的。 （D.吴） 2.浓缩拥挤剂对稀释反应物自缔合模型的总体影响被分析为拥挤剂与反应物种类之间排除体积和吸引相互作用的影响之和。 （A·明顿）