the pk shift of the purple-to-blue transition in the asp-85 -- -- glu , arg-82 -- -- ala , and arg-82 -- -- gln mutants and the similarity in the photocycle and photoelectrical signals of the asp-85 -- -- ala , asp-85 -- -- asn , and asp-212 -- -- asn mutants suggest the interaction between asp-85 , arg-82 , asp-212 , and the schiff base as essential for proton release .
C0061472
glu
C0017797
gln