STUDIES ON THE MECHANISM OF VISUAL EXCITATION

这项研究的长期目标是了解视觉的过程 分子水平上的激发。我们计划探索所有三个阶段的 视觉兴奋过程：初始转导事件，其中 被视觉色素吸收的光开始激发过程； 光激活视紫红质启动生化反应的机制 光感受器细胞内的事件和光感受器的控制 质膜通透性。我们不仅要研究脊椎动物的杆状物，而且 还将开发使用单克隆抗体的方法来轻松纯化 大量锥体和无脊椎动物的光感受器及其 相关的视觉色素。虽然鲜为人知的生化或 从生物物理的角度来看，前者的缺陷是造成这两种色素 治疗色盲。我们计划研究这两个地区的结构变化 视紫红质转化为ITS时的发色团和载脂蛋白 初级光产物，特别是寻找光能的证据 通过电荷分离转化为化学能的。我们会 调查可能的约束的性质和结构基础 二价阳离子通过视紫红质，以及光引发的相互作用 视紫红质与参与cGMP新陈代谢的酶在视杆中。的确有 越来越多的证据表明，视网膜色素变性的某些方面可能是由于 光激活酶系统的缺陷。为了调查这些 我们将使用各种各样的技术，包括蛋白质和 生色团修饰；和圆二色，低温， 荧光和振动光谱学。最后，我们将研究 分离纯化对棒状膜离子通道的控制 质膜和离子通道均使用单抗。

The long term goal of this research is to understand the process of visual excitation at the molecular level. We plan to explore all three stages of the visual excitation process: the intitial transduction event, where light absorbed by the visual pigment starts the excitation process; the mechanism by which the photo-activated rhodopsin initiates the biochemical events within the photoreceptor cell; and the control of photoreceptor plasma membrane permeability. We will study not only vertebrate rods, but also will develop methods using monocolonal antibodies to easily purify large quantities of cone and invertebrate photoreceptors and their associated visual pigments. While little is known biochemically or biophysically about either pigment, defects in the former are responsible for color blindness. We plan to study the structural changes in both the chromophore and the apoprotein when rhodopsin is transformed into its primary photoproduct and in particular look for evidence of light energy being transformed to chemical energy by charge separation. We will investigate both the nature and structural basis for probable binding of divalent cations by rhodopsin, and for the light initiated interaction of rhodopsin with enzymes involved in cGMP metabolism in the rods. There is growing evidence that certain aspects of retinitis pigmentosa may be due to defects in the light activated enzyme system. To investigate these interactions we will use a wide variety of techniques including protein and chromophore modification; and circular dichroic, low temperature, fluorescence, and vibrational spectroscopy. Finally we will study the control of ion channels in rod membranes by trying to isolate and purify both the plasma membrane and the ion channels using monoclonal antibodies.