The binding of secondary chromophore for thermally stable rhodopsin makes more stable with temperature

Abstract Microbial rhodopsin is a transmembrane protein that functions with chromophore and regulated by light. In nature, regulation through the retinal plays an important role in physiological phenomena. However, living organisms soil, sea, freshwater synthesize carotenoids preferentially over biosynthetic pathway. Evolution has extended energy conversion photosystem additional pigments act as antennae. Previously, Gloeobacter xanthorhodopsin have been reported to form secondary chromophores carotenoids. this study, we report thermophilic (TR) Tara76 rhodopsin, latter of which classified blue light‐absorbing proteorhodopsin, can canthaxanthin (CAN). TR were found exhibit high thermal stabilities photophysical properties following their interaction CAN. Isothermal titration calorimetry analysis, spectral shift measurements, exciton analysis used examine interactions these rhodopsins It was increased stability toward temperature pH highly efficient formation, addition rapidly recruiting at rate approximately twice obtained absence