Measurement of biomolecular interactions and association via light scattering

通过光散射测量生物分子相互作用和缔合

• 批准号: 8741359
• 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/8741359
• 关键词: Accounting; Amines; Data; Diffusion; Dissociation; Equilibrium; Exclusion; Guanidinium Chloride; Guanine Nucleotides; Guanosine Triphosphate; Laboratories; Light; Measurement; Modeling; Molecular Conformation; Molecular Weight; Monitor; Oxides; Phase Transition; Potassium; Proteins; Solutions; Techniques; Thermodynamics; analog; light scattering; macromolecule; protein function; stoichiometry

1. The effect of guanidine hydrochloride (GuHCl) and trimethyl-N-amine oxide (TMAO) upon the equilibrium dissociation of tetrameric to dimeric cyanmethemoglobin (CNmetHb) was studied by measurement of dynamic light scattering. This measurement yields the intensity average diffusion coefficient of the protein, which increases as the protein dissociates. The results showed that the increasing tendency of CNmetHb to dissociate with added GuHCl may be inhibited by addition of sufficient amounts of TMAO. The stabilizing effect of TMAO is attributed largely to volume exclusion (D. Wu). 2. The self-association of the bacterial septation protein FtsZ in the presence of GTP or a GTP analogue, GMPCPP, and 500 mM potassium was studied as a function of protein and Mg concentration using single-angle and multi-angle static light scattering. The results reveal that when the concentration of protein exceeds a Mg-dependent critical value, FtsZ undergoes a concerted formation, akin to a second-order phase transition to a narrow distribution of high molecular weight oligomers with a stoichiometry of ca 100 (GTP) or 160 (GMPCPP). Above the transition concentration, the amount, but not the size, of oligomer increases, while that of low molecular weight species remains roughly constant (Monterroso, Rivas). All of the data obtained from the several types of measurements may be accounted for semiquantitatively in the context of a model, according to which the stable oligomer is a cyclic species, the size of which reflects the tendency of the protein fibrils to flex or curve in solution in the presence of different concentrations of Mg and the particular guanine nucleotide present (B. Monterroso, G. Rivas, CIB).

1.通过动态光散射测量研究了盐酸胍（GuHCl）和三甲基-N-氧化胺（TMAO）对四聚体到二聚体氰化高铁血红蛋白（CNmetHb）平衡解离的影响。 该测量产生蛋白质的强度平均扩散系数，该系数随着蛋白质解离而增加。 结果表明，添加足够量的TMAO可以抑制CNmetHb与添加的GuHCl解离的增加趋势。 TMAO 的稳定作用很大程度上归因于体积排除 (D. Wu)。 2.使用单角度和多角度静态光散射，研究了在 GTP 或 GTP 类似物、GMPCPP 和 500 mM 钾存在下细菌分隔蛋白 FtsZ 的自缔合作为蛋白质和 Mg 浓度的函数。 结果表明，当蛋白质浓度超过 Mg 依赖性临界值时，FtsZ 会协同形成，类似于二级相变，形成化学计量为 ca 100 (GTP) 或的窄分布高分子量低聚物。 160（GMPCPP）。 高于转变浓度时，低聚物的数量增加，但尺寸不增加，而低分子量物质的数量基本保持不变（Monterroso，Rivas）。 从几种类型的测量获得的所有数据可以在模型的背景下半定量地解释，根据该模型，稳定的低聚物是环状物质，其大小反映了蛋白质原纤维弯曲或弯曲的趋势。溶液中存在不同浓度的镁和特定的鸟嘌呤核苷酸（B. Monterroso、G. Rivas、CIB）。