ROLE OF HYDROXYL-BEARING AMINO-ACIDS IN DIFFERENTIALLY TUNING THE ABSORPTION-SPECTRA OF THE HUMAN RED AND GREEN CONE PIGMENTS
ROLE OF HYDROXYL-BEARING AMINO-ACIDS IN DIFFERENTIALLY TUNING THE ABSORPTION-SPECTRA OF THE HUMAN RED AND GREEN CONE PIGMENTS
复制标题
DOI：
10.1111/j.1751-1097.1993.tb04956.x
复制
发表时间：
1993-11-01
影响因子：
3.3
通讯作者：
NATHANS, J
中科院分区：
文献类型：
--
作者：
MERBS, SL;NATHANS, J
人类红色和绿色锥状色素在15或16个氨基酸上不同，这取决于比较的多态性变体。这些氨基酸差异中的七个涉及羟基的引入或去除。这些差异之一，在位置180的丝氨酸丙氨酸的取代，被发现以前产生5 nm的蓝移。为了确定剩余的六个羟基基团的差异在调谐人类红色和绿色色素的吸收光谱中的作用，我们已经研究了六个定点突变体，其中单个氨基酸从绿色色素已被取代的红色色素中的相应残基。在277位的酪氨酸被苯丙氨酸取代和285位的苏氨酸被丙氨酸取代后，分别观察到7和14 nm的蓝移。在位置65，230，233和309处的单取代产生的光谱位移为1 nm或less. These数据与基于灵长类动物色素之间的序列比较和牛视紫红质的定点突变体的性质的模型吻合得很好。在比较红-绿混合颜料的吸收光谱时观察到的非加性效应仍有待解释。
The human red and green cone pigments differ at either 15 or 16 amino acids, depending upon which polymorphic variants are compared. Seven of these amino acid differences involve the introduction or removal of a hydroxyl group. One of these differences, a substitution of alanine for serine at position 180, was found previously to produce a 5 nm blue shift. To determine the role of the remaining six hydroxyl group differences in tuning the absorption spectra of the human red and green pigments, we have studied six site-directed mutants in which single amino acids from the green pigment have been substituted for the corresponding residues in the red pigment. Blue shifts of 7 and 14 nm were observed upon substitution of phenylalanine for tyrosine at position 277 and alanine for threonine at position 285, respectively. Single substitutions at positions 65, 230, 233, and 309 produced spectral shifts of 1 nm or less. These data are in good agreement with a model based upon sequence comparisons among primate pigments and with the properties of site-directed mutants of bovine rhodopsin. Nonadditive effects observed in comparing the absorption spectra of red-green hybrid pigments remain to be explained.