HELIX-COIL DYNAMICS OF NATURALLY OCCURRING PEPTIDES

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。子项目及 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。 螺旋不仅普遍存在于蛋白质中，而且已知可对各种序列进行采样。然而，以前的实验研究的折叠动力学的单体α-螺旋主要集中在丙氨酸为基础的肽。由于这种富含丙氨酸的序列在蛋白质中很少遇到，因此假设天然存在的α-螺旋将显示与富含丙氨酸的肽类似的折叠速率是不谨慎的。鉴于二级结构形成在现有蛋白质折叠模型中的重要作用，非常需要进一步研究α-螺旋折叠动力学的序列依赖性。 在这里，我们研究了松弛动力学的天然存在的α-螺旋肽衍生自螺旋蛋白质，以及设计的螺旋肽，是稳定的盐桥，响应于激光诱导的T-跳跃使用红外（IR）光谱。该项目的目标是提供对α-螺旋的折叠机制和侧链-侧链相互作用的动力学作用的进一步见解。

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. Helices are not only ubiquitous in proteins, but are also known to sample a wide variety of sequences. However, previous experimental studies on the folding dynamics of monomeric alpha-helices have focused mainly on alanine-based peptides. Since such alanine-rich sequences are rarely encountered in proteins, it is thus imprudent to assume that naturally occurring alpha-helices would show similar folding rates as those of alanine-rich peptides. In light of the important role of secondary structure formation in existing protein folding models, there is a strong need for further investigation of the sequence-dependence of alpha-helix folding kinetics. Herein, we study the relaxation kinetics of a naturally occurring alpha-helix peptide derived from a helical protein as well as a designed helical peptide that is stabilized by salt-bridges, in response to a laser-induced T-jump using infrared (IR) spectroscopy. The goal of this project is to provide further insights into the folding mechanism of alpha-helices and the kinetic role of sidechain-sidechain interactions.