SEMI-ANALYTIC APPROACHES TO SPIN RELAXATION IN PROTEINS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 ESR和NMR弛豫在蛋白质动力学研究中已被证明是有用的。我们开创了缓慢松弛局部结构（SRLS）的方法来解释它们。在这方面，它是非常成功的，特别是对于慢动ESR谱。在其目前，相对方便的实现，SRLS方法仍然是计算要求，它们是基于（过阻尼）扩散运动的简化，是一个介观（不同于原子）的方法。开展这一项目是为了改进自力更生和最不发达国家的做法。例如，在势阱中重新定向的蛋白质侧链将以扭转振荡的形式表现出惯性效应。此外，蛋白质的骨架动力学必然涉及集体动力学，这可以以相对简单的方式通过在全局扩散的存在下耦合几个惯性线性旋转子来建模。另一个目标是获得限制分析模型，减少ESR和NMR自旋弛豫应用中的计算挑战，并确定其有效性范围。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Both ESR and NMR relaxation have proved useful in the study of protein dynamics. We have pioneered the slowly-relaxing local structure (SRLS) approach to their interpretation. It has been very successful, especially for the slow-motional ESR spectra, in this regard. In its present, relatively convenient implementations, the SRLS approaches are still computationally demanding; they are based on the simplification of (overdamped) diffusive motions, and are a mesoscopic (as distinct from an atomic) approach. This project was undertaken to provide improvements on the SRLS approach. For example, a protein side-chain which reorients in a potential well, will exhibit inertial effects in the form of torsional oscillations. Also the backbone dynamics of a protein necessarily involves collective dynamics, which could, in a relatively simple manner, be modeled by the coupling of several inertial linear rotators in the presence of global diffusion. Another objective is to obtain limiting analytical models that reduce the computational challenges in application to ESR and NMR spin relaxation, and to determine their range of validity.