Recovery of Red Fluorescent Protein Chromophore Maturation Deficiency through Rational Design
Figure 5
(A and B) Introduction of the AYC motif results in π-stacking interactions between the chromophore and Tyr197 in both mPlumAYC (A) and mPlumAYC-E16A (B). H-bonding interactions with Lys70 are illustrated with dashed lines. These interactions combine to sequester the terminal amino group of Lys70 away from the chromophore. (C and D) Comparisons of Lys70-to-chromophore distance are illustrated between mPlum (purple), mPlumAYC (yellow), and mPlumAYC-E16A (blue) (C), as well as between mCherry (pink), mPlum (purple), and mPlum-E16P (red) (D). A dotted line connects the NZ atom of Lys70 in mPlum to the O2 atom of the mPlum green (C) or red (D) chromophore. Note that Lys70 in mPlum (PDB code 2QLG [21]) adopts a slightly different conformation in the green versus red chromophore contexts. All proteins were aligned by the atoms of their imidazolinone ring.