SYNTHETIC RETINAL PIGMANTS AND BINDING PROTEINS

描述(摘自申请人的摘要)：11-顺式异构体 维生素A醛是视觉色素视紫红质的生色团， 可以被认为是整个视觉过程的中心。这么小 分子(Mw 300)通过质子化的Schiff碱与赖氨酸296连接 形成视紫红质的蛋白质，在这种形式下，发色团持有 非活性构象的蛋白质。当一个光子被吸收时 光，生色团被异构化为全反式异构体并诱导 使蛋白质处于活性状态的蛋白质的构象变化 构象。脱脂蛋白视蛋白，它不包含视网膜和 因此，它在活动或非活动配置中的“锁定”部分 活动。建议使用视紫红质激酶的生化检测方法 完整光感受器组合的活性和生理研究 用类似的视网膜来探索这些发现。这个实验室将 利用质谱学方法探索蛋白质结构 交联剂来检查两者的三维结构 蛋白质的活性形式和非活性形式。拟研究的表格包括： 视蛋白(无发色团；部分活性)、视紫红质(11顺式视网膜； 不活跃)和后视紫红质II(全反式视网膜；活跃)。 有人建议，某些涉及视网膜的临床疾病 变性可能是由于信号转导的长期激活引起的。 卡斯卡德。蛋白质很可能被固定在不活跃或安静的状态 对视网膜的正常生理功能是必不可少的。在……里面 此外，在维甲酸的代谢和运输过程中的许多步骤 视网膜和RPE定义不清，值得研究。使用视网膜 在这里开发的类似物，调查人员建议进一步探索 棒状和锥状视觉颜料活性的关键控制 使用这些类比来研究RPE中一种特别令人困惑的蛋白质。 其他项目包括绘制发色团结合位点图和 视紫红质的胞质环，以及视紫红质的作用 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.