A new allosteric model of hemoglobin: pressure and comp*

了解血红蛋白(Hb)的结构-功能关系具有重要的生物医学意义。长期以来，Monod、Wyman和Changeux的两态变构模型(MWC)一直被用来描述合作氧与Hb结合的各种结构、平衡和动力学数据。根据上述母体赠款最近开展的工作挑战了MWC模型所依据的基本假设，并指出氧亲和力主要由四元结构决定。我的实验室工作表明，需要一个扩展的MWC变构模型来完全解释变构效应引起的氧结合等温线的变化。这一建议旨在研究我们的配体结合研究提出的扩展MWC模型的特征，使用实验和计算相结合的方法，旨在补充我们之前使用HBA杂化的工作。它以高分辨率的FLN激光光谱学实验方法为特色，不仅将用于获取振动分辨的光谱，还将用于进行压力研究。这一建议的主要创新之处在于应用了一种光谱技术，旨在监测作为热力学参数的流体静压，并结合了一种旨在模拟结合变构效应器对HB三元和四元结构影响的计算方法。匈牙利实验室(FIDY)将进行高分辨率光谱实验和压力研究以及计算工作。所需的HBA杂交物的合成将在我的实验室(Yonetani)以及FT-拉曼实验中完成。

Understanding the structure-function relationships of hemoglobin (Hb) is of great biomedical significance. The two-state allosteric model of Monod, Wyman, and Changeux (MWC) has long been used to provide a description of a wide variety of structural, equilibrium and kinetic data on cooperative oxygen binding to Hb. Recent work performed under the above-mentioned parent grant has challenged the fundamental assumption underlying the MWC model and stating that oxygen affinity is primarily determined by the quaternary structure. Work performed in my laboratory shows that an extended MWC allosteric model is required to fully account for the variation of oxygen binding isotherms induced by allosteric effectors. This proposal aims at investigating features of the extended MWC model suggested by our ligand binding studies using a combined experimental and computational approach designed to complement our previous work using HbA hybrids. It features a high-resolution FLN laser spectroscopy experimental approach which will be used - not only for the acquisition of vibronically-resolved spectra - but also to perform pressure studies. The essential originality of this proposal resides in the application of a spectroscopic technique designed to monitor hydrostatic pressure as a thermodynamic parameter combined to a computational approach aimed at modeling the effect of binding allosteric effectors on the Hb tertiary and quaternary structure. The Hungarian laboratory (Fidy) will carry out the high-resolution spectroscopy experiments and pressure studies as well as the computational work. The synthesis of the required HbA hybrids will be done in my laboratory (Yonetani) as well as the FT-Raman experiments.