MECHANISM OF VISUAL EXCITATION

我们的长期目标是阐明生物化学和生物物理 视觉兴奋和感光体代谢的潜在机制。 我们 方法是在几个组织中解决重要的相关问题 感光细胞的水平。 这些层面首先是视觉层面 色素本身，尤其是鸡锥色素， 建立其氨基酸序列，我们计划纯化和研究 色素生物降解（振动光谱，漂白动力学）。 第二、 在光对色素的作用的层面上，我们将寻求了解 原子弹储存光子能量的性质 光产物，bathorhodopsin，和metarhodopsin II的性质， 使其与GTP结合蛋白相互作用并激活GTP结合蛋白， 转导素 第三是感光膜的水平。 我们想 光感受器表面电位控制的测量与研究 膜，因为表面电位将对膜的 带电底物（例如cGMP）、辅因子（例如GRP）和 光感受器膜表面附近的酶（例如，转导素）， 发生活化和一些随后的酶促事件。 我们还计划 在澄清拓扑结构的视紫红质的膜，并将纯化 视锥细胞感光膜 四是水平感光细胞， 特别是关于转导机制本身， 递质和视网膜细胞内的其他关键小分子。 这里 我们将利用新的方法来转导（拉曼差异 光谱、阳离子结合、金属II引发的构象变化）和 利用磷31核磁共振波谱研究细胞内 体内的递质和代谢物。 这种综合方法将提供 不仅对视觉兴奋和视网膜神经元的控制有了新的认识， 新陈代谢，而且还导致新的和更敏感的方式的发展 以测定体内视网膜的健康和代谢状态。

Our long term goal is to elucidate the biochemical and biophysical mechanisms underlying visual excitation and photoreceptor metabolism. Our approach is to attack important, related problems at several organizational levels of the photoreceptor cell. These levels are first, the visual pigments themselves, especially chicken cone pigments where, besides establishing their amino acid sequences, we plan to purify and study the pigments biophysically (vibrational spectra, bleaching kinetics). Second, at the level of the action of light on the pigments, we will seek to learn the nature of the storage of the photon's energy by the primary photoproduct, bathorhodopsin, and the properties of metarhodopsin II which allows it to interact with and activate the GTP binding protein, transducin. Third is the level of the photoreceptor membrane. We want to measure and study the control of the surface potential of photoreceptor membranes, since the surface potential will have profound effects on the concentration of charged substrates (e.g. cGMP), co-factors (e.g. GRP), and enzymes (e.g. transducin) near the surface of photoreceptor membranes where activation and some subsequent enzymatic events takes place. We also plan on clarifying the topology of rhodopsin in the membrane and will purify cone photoreceptor membranes. Fourth, is the level photoreceptor cell, especially with regard to the transduction machinery itself, and the transmitters and other key small molecules within the retinal cells. Here we will utilize new approaches to transducin (Raman difference spectroscopy, cation binding, meta II initiated conformational changes) and the use of phosphorus 31 NMR spectroscopy to study intracellular transmitters and metabolites in vivo. This integrated approach will offer not only new insight into visual excitation and the control of retinal metabolism, but also lead to the development of new and more sensitive ways to assay the health and metabolic state of the retina in vivo.