Single amino acid residue as a functional determinant of rod and cone visual pigments
Single amino acid residue as a functional determinant of rod and cone visual pigments
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DOI：
10.1073/pnas.94.6.2322
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发表时间：
1997-03-18
影响因子：
11.1
通讯作者：
Shichida, Y
中科院分区：
文献类型：
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作者：
Imai, H;Kojima, D;Shichida, Y
视杆细胞和视锥细胞感光细胞中的视觉转导过程始于不同类型视色素的光子吸收，正如预期的那样，由于视杆细胞和视锥细胞之间的功能差异，视杆视色素比视杆视色素、视紫红质表现出更快的 11-顺式视黄醛和视蛋白再生以及生理活性中间体（元 II）更快的衰减。 Li等选择了视锥细胞视色素具有与视紫红质电学上不同的氨基酸残基的三个氨基酸位置（64、122和150），制备了视紫红质突变体并增稠了绿色敏感视锥视色素。将Glu-122转化为绿色敏感视锥视色素将这些过程的速率改变为与视紫红质相似的速率。此外，视紫红质和鸡绿色敏感视锥色素之间122位残基的交换改变了它们激活视网膜G蛋白转导蛋白的效率，因此，122位氨基酸残基是视杆和视锥视色素的功能决定因素。
The visual transduction processes in rod and cone photoreceptor cells begin with photon absorption by the different types of visual pigments, Cone visual pigments exhibit faster regeneration from 11-cis-retinal and opsin and faster decay of physiologically active intermediate (meta II) than does the rod visual pigment, rhodopsin, as expected, due to the functional difference between rod and cone photoreceptor cells, To identify the amino acid residue(s) responsible for the difference in molecular properties between rod and cone visual pigments, we selected three amino acid positions (64, 122, and 150), where cone visual pigments have amino acid residues electrically different from those of rhodopsin, and prepared mutants of rhodopsin and thicken green-sensitive cone visual pigment, The results showed that the replacement of Glu-122 of rhodopsin by the residue containing green- or red-sensitive cone pigment converted rhodopsin's rates of regeneration and meta II decay into those of the respective cone pigments, whereas the introduction of Glu-122 into green-sensitive cone visual pigment changed the rates of these processes into rates similar to those of rhodopsin, Furthermore, exchange of the residue at position 122 between rhodopsin and chicken green-sensitive cone pigment interchanges their efficiencies in activating retinal G protein transducin, Thus, the amino acid residue at position 122 is a functional determinant of rod and cone visual pigments.