A conserved interaction with the chromophore of fluorescent proteins.

ABSTRACT: The chromophore of fluorescent proteins, including the green fluorescent protein (GFP), contains a highly conjugated imidazolidinone ring. In many fluorescent proteins, the carbonyl group of the imidazolidinone ring engages in a hydrogen bond with the side chain of an arginine residue. Prior studies have indicated that such an electrophilic carbonyl group in a protein often accepts electron density from a main-chain oxygen. A survey of high-resolution structures of fluorescent proteins indicates that electron lone pairs of a main-chain oxygen-Thr62 in GFP-donate electron density into an antibonding orbital of the imidazolidinone carbonyl group. This n→π* electron delocalization prevents structural distortion during chromophore excitation that could otherwise lead to fluorescence quenching.

SUBMITTER: Choudhary A 

PROVIDER: S-EPMC3324761 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature