Johnson R L, Grant K B, Zankel T C, Boehm M F, Merbs S L, Nathans J, Nakanishi K
Department of Chemistry, Columbia University, New York, New York 10027.
Biochemistry. 1993 Jan 12;32(1):208-14. doi: 10.1021/bi00052a027.
Five opsin cDNA clones were isolated from a goldfish retina cDNA library and sequenced. On the basis of homology to previously characterized visual pigments, one clone was identified as goldfish rod opsin and a second as a goldfish red cone opsin. Two rhodopsin-like clones were found to be similar to the chicken green opsin, a pigment which shares properties with both rod and cone pigments. A fifth clone was equally homologous to human blue cone opsin and human rod opsin. In order to characterize the spectral properties of the encoded pigments, the five clones were expressed in tissue culture cells and the apoproteins reconstituted with 11-cis-retinal. The wavelength of maximal absorption for goldfish rhodopsin is 492 nm and for the fifth pigment, identified as the goldfish blue pigment, 441 nm. Pigments encoded by the two rhodopsin-like clones absorb at 505 and 511 nm and are likely to correspond to the goldfish green pigment previously characterized by microspectrophotometry. The putative red cone opsin cDNA may encode a pigment that is a polymorphic variant of goldfish red since it absorbs maximally at 525 nm.
从金鱼视网膜cDNA文库中分离出五个视蛋白cDNA克隆并进行测序。根据与先前鉴定的视觉色素的同源性，一个克隆被鉴定为金鱼视杆视蛋白，另一个为金鱼红锥视蛋白。发现两个视紫红质样克隆与鸡绿视蛋白相似，鸡绿视蛋白是一种兼具视杆和视锥色素特性的色素。第五个克隆与人类蓝锥视蛋白和人类视杆视蛋白具有同等同源性。为了表征所编码色素的光谱特性，将这五个克隆在组织培养细胞中表达，并将脱辅基蛋白与11-顺式视黄醛重组。金鱼视紫红质的最大吸收波长为492nm，而被鉴定为金鱼蓝色素的第五种色素的最大吸收波长为441nm。由两个视紫红质样克隆编码的色素在505和511nm处有吸收，可能对应于先前通过显微分光光度法鉴定的金鱼绿色素。推测的红锥视蛋白cDNA可能编码一种色素，它是金鱼红色素的多态变体，因为它在525nm处有最大吸收。
