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Seeing red (and green): The first structural insight into the color tuning of color visual pigments is obtained by light-induced FTIR studies of monkey green and red retinal pigments in D2O. Their FTIR spectra are similar to those of rhodopsin in the low-frequency region but entirely different in the XH and XD stretching regions, providing insights into the chromophore–protein interactions in color pigments.
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Katayama et al. (2010) studied this question.
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