RUI: Phosphorescence Probe of Heme Protein Dynamics

对球状蛋白动态内部运动的详细了解是人们所寻求的，因为它对蛋白质的结构/功能关系的知识很重要，因为它们涉及到基础研究和涉及蛋白质药物生产和药物逻辑设计的工业研究的应用方面。主要研究者和学生报告了6-溴-2-硫酸萘酯（BNS）的磷光被血红素蛋白的血红素特异性猝灭。猝灭速率常数kq由激光诱导磷光的寿命测量确定，并用于判断血红素蛋白内部运动使血红素环可接近的程度。在这项研究中，将尝试用更大的磷光分子探针（例如9-溴-6-硫酸菲）代替BNS。此外，kq将测量几种酶促和非酶促血红素蛋白作为温度和溶剂条件的函数。最终目标是：1)估计蛋白质的瞬时波动大小，2)确定酶促血红素蛋白和非酶促血红素蛋白的动力学是否存在根本差异，3)比较天然蛋白质和蛋白质折叠的重要中间体（称为熔融球）的动力学，4)深入了解血红素蛋白复合物中血红素的可及性。5)确定血红蛋白三级结构动力学对分子氧的结合和释放是否重要。＊＊＊

9417885 Schuh A detailed understanding of the dynamic internal motion of globular proteins is sought because of its importance to a knowledge of the structure/function relationships of proteins as they pertain to fundamental research and to applied aspects of industrial research involving production of protein pharmaceuticals and the logical design of drugs. The principal investigator and students have reported that the phosphorescence of 6-bromo-2-naphthyl sulfate (BNS) is quenched specifically by the heme of heme proteins. The rate constant for quenching, kq, is determined from lifetime measurements of laser-induced phosphorescence and is used to judge the extent to which internal motion of heme proteins makes the heme rings accessible. In this research attempts will be made to substitute larger phosphorescent molecular probes (e.g. 9-bromo-6- phenanthrene sulfate) in place of BNS. Also kq will be measured for several enzymatic and non-enzymatic heme proteins as a function of temperature and solvent conditions. %%% The ultimate goals are to: 1) estimate the size of transient fluctuations in proteins, 2) determine whether there are fundamental differences in the dynamics of enzymatic and non- enzymatic heme proteins, 3) compare the dynamics of native proteins and an important intermediate in protein folding, called the molten globule, 4) gain insight into the accessibility of the hemes in heme protein complexes, and 5) determine whether tertiary structural dynamics of hemoglobin is important to the binding and release of molecular oxygen. ***