Molecular Structure and Function Relations of Transients. Photoreceptors: Time-Resolved Infrared Studies

这项建议旨在提供基本的见解，在光敏色素光感受器(植物生长和光反应控制剂)和细菌视紫红质(光驱动的质子泵)中，蛋白质结构如何与蛋白质功能和反应性有关。这项研究的总体目标是利用时间分辨红外光谱，通过跟踪蛋白质酰胺I和II区、羧基、特定氨基酸(即色氨酸和酪氨酸)和蛋白质光中间体的动态，来研究从皮秒到千秒的时间范围内的光诱导构象变化和动力学中间体。除了动态了解光和光敏的双三烯光敏色素之间的相互作用外，研究人员还将确定a)亚胺氢与附近反离子之间可能的氢键的方向和强度；以及b)C=N频移附近的正电荷或负电荷对双三烯生色团和视网膜Schiff碱生色团质子化的影响。这项建议还旨在了解如何利用光敏色素和细菌视紫红质的可逆光控制特性来制造光生物传感器或光器件。

This proposal seeks to provide fundamental insight into how, in the phytochrome photoreceptor (the plant growth and photoresponse control agent) and bacteriorhodopsin ( a light driven proton pump), protein structure relates to protein function and reactivity. The overall goal of this research is to study, using time-resolved infrared spectroscopy from picosecond to kilosecond time regimes, light-induced conformational changes and kinetic intermediates by following the dynamics of the protein amide I and II regions, carboxylic groups, specific amino acid (i.e. tryptophan and tyrosine) and protein photointermediates. In addition to the dynamic understanding of the interaction between light and the photosensitive bilitriene phytochrome, the investigatior will determine a) orientation and strenght of possible hydrogen bonds between the imine hydrogen and a nearby counter ion; and b) effects of a positive or negative charge near the C=N frequency shift upon protonation of both the bilitriene chromophore and the retinal Schiff's base chromophore. This proposal is also aimed at learning how the reversible photocontrol properties of phytochrome and bacteriorhodopsin can be used to produce light biosensors or photodevices.