involving a rapid ( approximately 1 micros ) concerted change in the orientation of both retinal and tyrosine and/or tryptophan side chains concomitant with alterations in the local protein environment of these chromophores . as well as slower changes ( approximately 100 micros ) of the microenvironment of aromatic amino acid residues concomitant with pk changes in at least two types of proton-binding sites .
C0041249
tryptophan
C0301713
aromatic amino