Phosphorescence Probe of Heme Protein Dynamics

详细了解球状蛋白的动态内部运动对于了解蛋白质的结构/功能关系至关重要。Schuh博士最近发现，血红素蛋白的血红素对6-溴-2-硫酸萘酯的磷光猝灭可用于评估细胞色素c和肌红蛋白的瞬时开口。猝灭速率常数kq由激光诱导磷光的寿命测量确定，用于估计血红素蛋白运动使假血红素环可接近的程度。如果发现1-溴蒽、溴蒽、9-溴菲蒽和伊红是合适的磷光探针，则建议使用kq与分子探针大小的相关性来估计血红素蛋白肌红蛋白、血红蛋白、细胞色素c和细胞色素c过氧化物酶。最终目标是：1)估计蛋白质的瞬时波动的大小，2)确定氧化还原蛋白中血红素环的可及性对电子进出蛋白质是否重要，3)确定血红蛋白低聚物在二氧分子结合和释放过程中三级结构的瞬时变化的重要性。这些目标的实现将提高我们对蛋白质结构/功能关系的理解。

A detailed understanding of the dynamic internal motion of globular proteins is of fundamental importance to a knowledge of the structure/function relationships of proteins. Dr. Schuh has recently discovered that quenching of the phosphorescence of 6-bromo-2-naphthyl sulfate by the heme of heme proteins can be used to assess transient openings in cytochrome c and myoglobin. The rate constant for quenching, kq, is determined from lifetime measurements of laser-induced phosphorescence and is used to estimate the extent to which motion of heme proteins makes the prosthetic heme rings accessible. If 1-bromopyrene, bromoanthracenes, 9-bromophenanthrenes, and eosin, are found to be suitable phosphorescent probes, it is proposed that the correlation of kq with the size of the molecular probe be used to estimate the size of transient openings in the heme proteins myoglobin, hemoglobin, cytochromes c and cytochrome c peroxidase. The ultimate goals are to: 1) estimate the size of transient fluctuations in proteins, 2) determine whether accessibility of the heme ring in redox proteins is important for the flow of electrons in and out of the proteins, and 3) determine the importance of transient changes in tertiary structure of the oligomers of hemoglobin during the binding and release of dioxygen molecules. The achievement of these goals will improve our understanding of structure/function relationships in proteins.