A Photoacoustic Calorimetric Study of the Protein Dynamics of Myoglobin

彼得斯博士提议研究蛋白质结构如何控制 焓和体积变化的动力学 一氧化碳从肌红蛋白中分解出来 的 分析方法是时间分辨光声 量热法。 时间分辨光声量热法 测量焓和体积变化的动态， 由光引发的反应。 的分辨率 实验是这样的，对于发生在更少的反应， 在100纳秒内， 变化是可以衡量的。 对于发生在100 纳秒和20微秒的动态焓， 可以获得体积变化。 在过去的三年里，博士。 彼得斯一直在研究焓和体积的动力学 与碳的光解离有关的变化 从抹香鲸、马和人类肌红蛋白中提取的一氧化碳。 他 发现了抹香鲸中一种新的中间体的证据 在碳分解时形成的肌红蛋白 一氧化碳，它涉及盐桥的断裂和再- 蛋白质结构的组织。 遵循这些 彼得斯博士想调查的初步观察 这种蛋白质结构变化的本质。 他将审查 抹香鲸和人类肌红蛋白的突变体，由 定点诱变，以确定 阻碍了这种中间体的形成。 此外，使用 他将检查pH滴定曲线 肌红蛋白的能量学和动力学， 确定是否发生了结构性变化， 可能影响某些氨基酸酸度的蛋白质。

Dr. Peters proposed to study how protein structure controls the dynamics of the enthalpy and volume changes associated with the dissociation of carbon monoxide from myoglobin. The method of analysis is time-resolved photoacoustic calorimetry. Time-resolved photoacoustic calorimetry measures the dynamics of the enthalpy and volume changes for reactions that are initiated by light. The resolution of the experiment is such that for reactions which occur in less than 100 nanoseconds, the sum of the enthalpy and volume changes are measured. For reactions occurring between 100 nanoseconds and 20 microseconds the dynamics of enthalpy and volume changes can be obtained. For the past three years Dr. Peters has been examining the dynamics of enthalpy and volume changes associated with the photodissociation of carbon monoxide from sperm-whale, horse and human myoglobins. He has found evidence for a new intermediate in sperm-whale myoglobin that is formed upon the dissociation of carbon monoxide which involves the breaking of a salt bridge and re- organization of the protein structure. Following these initial observations Dr. Peters would like to investigate the nature of this protein structural change. He will examine mutants of sperm-whale and human myoglobin, engineered by site directed mutagenesis, to determine the origin of the barrier to the formation of this intermediate. Also, using combinations of buffers he will examine pH titration curves for the energetics and dynamics of the myoglobins in order to ascertain if structural changes are occurring within the protein that may effect the acidity of some amino acids.