Yokoyama S
Department of Biology, Syracuse University, New York, USA.
Annu Rev Genet. 1997;31:315-36. doi: 10.1146/annurev.genet.31.1.315.
A central unanswered question in phototransduction is how photosensitive molecules, visual pigments, regulate their absorption spectra. In nature, there exist various types of visual pigments that are adapted to diverse photic environments. To elucidate the molecular mechanisms involved in the adaptive selection of these pigments, we have to identify amino acid changes of pigments that are potentially important in changing the wavelength of maximal absorption (lambda max) and then determine the effects of these mutations on the shift in lambda max. The desired mutants can be constructed using site-directed mutagenesis, expressed in tissue culture cells, and the functional effect of virtually any such mutant can be rigorously determined. The availability of these cell/molecular methods makes vision an ideal model system in studying adaptive mechanisms at the molecular level. The identification of potentially important amino acid changes using evolutionary biological means is an indispensable step in elucidating the molecular mechanisms that underlie the spectral tuning of visual pigments.
光转导中一个尚未解决的核心问题是光敏分子（视觉色素）如何调节其吸收光谱。在自然界中，存在各种适应不同光照环境的视觉色素。为了阐明这些色素适应性选择所涉及的分子机制，我们必须确定在改变最大吸收波长（λmax）方面可能重要的色素氨基酸变化，然后确定这些突变对λmax 位移的影响。所需的突变体可以使用定点诱变构建，在组织培养细胞中表达，并且几乎任何此类突变体的功能效应都可以得到严格确定。这些细胞/分子方法的可用性使视觉成为研究分子水平适应机制的理想模型系统。利用进化生物学方法鉴定潜在重要的氨基酸变化是阐明视觉色素光谱调谐基础分子机制的不可或缺的一步。
