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THE ULTRAVIOLET FLUORESCENCE OF BACTERIORHODOPSIN AND THE LOCATION OF TRYPTOPHANYL RESIDUES
Author(s) -
Sherman Warren V.
Publication year - 1981
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1981.tb05431.x
Subject(s) - bacteriorhodopsin , chemistry , fluorescence , photochemistry , tryptophan , microviscosity , quenching (fluorescence) , ultraviolet , crystallography , membrane , materials science , biochemistry , amino acid , physics , quantum mechanics , optoelectronics
— The ultraviolet fluorescence spectrum of bacteriorhodopsin is characterized by emission from an ensemble of internal, surface and exposed Trp residues. The temperature dependence of fluorescence yields exhibits a discontinuity at about 30°C coincident with previously observed transitions in membrane lipid microviscosity, photocycle lifetime and photoconductivity. Quenching at high pH coincides with ionization of Tyr and an emission red shift to a spectrum typical of that of tyrosinate. Guanidine hydrochloride produces only partial protein denaturation, increasing the number of exposed Trp by 50%. While exposed Trp in native bacteriorhodopsin are in the minority, they represent a higher proportion of total Trp than is found in rhodopsin of animal rod outer sections.