SYNTHETIC RETINAL PIGMANTS AND BINDING PROTEINS

描述（改编自申请人的摘要）： 维生素A醛是视色素视紫红质的发色团， 可以被认为是整个视觉过程的中心。 这个小 分子（MW 300）通过质子化的席夫碱与赖氨酸296连接， 蛋白质形成视紫红质，并且在这种形式下，发色团保持 处于非活性构象的蛋白质。 在吸收光子的同时， 光，发色团被异构化为全反式异构体，并诱导 蛋白质中的构象变化，使蛋白质处于其活性状态， 构象 脱辅基蛋白视蛋白，它不包含视网膜和 因此，其在活动或非活动配置中的“锁定”具有部分 活动 建议采用视紫红质激酶的生化措施 对完整光感受器的活性和生理学研究 与类似的视网膜来探索这些发现。 该实验室将 利用质谱方法探测蛋白质结构 交联剂，以检查这两个的三维结构， 蛋白质的活性和非活性形式。 需要研究的形式有： 视蛋白（无发色团;部分活性），视紫红质（11-顺式视网膜; 非活性）和变视紫红质II（全反式视网膜;活性）。 已经有人提出，某些涉及视网膜病变的临床疾病 变性可由转导的延长激活引起 级联。 将蛋白质固定在其非活性或安静状态是可能的 对视网膜的正常生理功能至关重要。 在 此外，维生素A的代谢和运输中的许多步骤， 视网膜和RPE是不明确的，需要研究。 使用视网膜 类似物在这里开发，研究人员建议进一步探索 视杆细胞和视锥细胞视色素活性的关键控制， 使用这些类似物来检测RPE中一种特别复杂的蛋白质。 其他项目包括绘制发色团结合位点， 视紫红质的胞质环，以及研究视紫红质环的作用。 RPE-膜蛋白RPE-65

DESCRIPTION (Adapted from applicant's abstract): The 11-cis isomer of vitamin A aldehyde is the chromophore of the visual pigment rhodopsin and can be regarded as being central to the entire visual process. This small molecule (MW 300) links, via a protonated Schiff base, with lysine 296 of the protein to form rhodopsin and, in this form, the chromophore holds the protein in an inactive conformation. Upon the absorption of a photon of light, the chromophore is isomerized to the all-trans isomer and induces conformational changes in the protein that place the protein in its active conformation. The apoprotein opsin, which does not contain the retinal and thus its "lock" in the active or inactive configuration, has partial activity. It is proposed to use biochemical measures of rhodopsin kinase activity and physiological studies on intact photoreceptors in combination with analogs of retinal to explore these findings. This laboratory will probe the protein structure with mass spectral approaches utilizing crosslinking agents to examine the three-dimensional structure of both the active and inactive forms of the protein. The forms to be studied are: opsin (no chromophore; partially active), rhodopsin (11-cis retinal; inactive) and metarhodopsin II (all-trans retinal; active). Suggestions have been made that certain clinical disorders involving retinal degeneration may arise from prolonged activation of the transduction cascade. The fixing of the protein in its inactive or quiet state is likely to be essential to the normal physiological function of the retina. In addition, many steps in both the metabolism and transport of retinoids in the retina and RPE are ill-defined and warrant study. Using the retinal analogs developed here, the investigators propose to further explore the critical control of the activity of the rod and cone visual pigments and to use these analogs in examining a particularly perplexing protein in the RPE. Other projects include mapping of the chromophore-binding site and cytoplasmic loops of rhodopsin, and investigation of the role of the RPE-membrane protein, RPE-65.