Energy Transfer in Native Proteins

Abstract

For several reasons it seems unlikely that the peptide bonds in proteins can act as transmitters of electronic excitation under normal conditions. First, electronic transitions should occur at very high frequencies, i.e. in the UV region at 190 nm, and the fluorescence quantum yield is almost zero. Second, peptide bonds have relatively intense vibrations in the IR region. Therefore, very fast internal conversion should take place. Third, peptide bonds in proteins are surrounded by amino acid residues, which can efficiently deactivate the excited peptide bonds.