Molecular determinants of human red/green color discrimination
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Determination of Photoreceptor Cell Spectral Sensitivity in an Insect Model from In Vivo Intracellular Recordings
Published on: February 26, 2016
A B Asenjo1, J Rim, D D Oprian
1Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254.
Abstract:
The human red and green color vision pigments are identical at all but 15 of their 364 amino acids, and yet their absorption maxima differ by 31 nm. In an extensive mutagenesis study, including a set of 28 chimeric proteins modeled after pigments in the color-deficient human population and an additional 30 single and multiple point mutants, the spectral difference between these 2 pigments is shown to be determined by 7 and only 7 amino acid residues. In going from the red pigment to the green pigment, the 7 residues are Ser116-->Tyr, Ser180-->Ala, Ile230-->Thr, Ala233-->Ser, Tyr277-->Phe, Thr285-->Ala, and Tyr309-->Phe.
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