COMPOUND RELATED TO PROTEIN THE TWO CHAINS IN ASSYMETRIC UNIT HAD THE SAME SEQUENCE EXCEPT AT THE ...COMPOUND RELATED TO PROTEIN THE TWO CHAINS IN ASSYMETRIC UNIT HAD THE SAME SEQUENCE EXCEPT AT THE CHROMPHORE. THE CH6 OF CHAIN A AND NRQ OF CHAIN B BOTH COME FROM THE SAME PARENT RESIDUES MET, TYR AND GLY. AUTHOR STATED THAT THE CA1-N BOND OF CH6 IS SINGLE BOND BUT THE CA1-N OF NRQ IS DOUBLE BOND THAT EXTENDS THE CHROMOPHORE CONJUGATION SYSTEM. THIS IS THE ONLY DIFFERENCE BETWEEN CR2 AND CR3. AUTHOR ALSO STATED THAT CR2 IS A RED FLUORESCENT PROTEIN CHROMOPHORE, WHILE CR3 IS A GREEN FLUORESCENT PROTEIN CHROMOPHORE, DUE TO DIFFERENT CONJUGATION LENGTH.