to study the mechanism of light-dependent proton translocation by bacteriorhodopsin , we have introduced single-codon changes in the gene so as to produce the following specific amino acid substitutions in the protein : tyr-185 to phe , pro-186 to leu , trp-189 to phe , ser-193 to ala , and glu-194 to gln .
C0061472
glu
C0017797
gln