AMCA to TAMRA long range resonance energy transfer on a flexible peptide

Abstract

Förster resonance energy transfer between 7-amino-4-methyl-3-coumarinylacetic acid, (AMCA, donor) and 5-carboxytetramethylrhodamine, (TAMRA, acceptor) bound to Lys(AMCA)-Gly-Pro-Arg-Ser-Leu-Ser-Gly-Lys(TAMRA)-NH2 peptide is demonstrated by various spectroscopic techniques in glycerol at room temperature.In particular, nonexponential character of fluorescence intensity decay evidences the distance distribution between the donor and acceptor sites resulting from the flexibility of the peptide. Numerical analysis of the fluorescence decay yields the distance distribution parameters. The results obtained are consistent with those obtained from steady-state fluorescence indicating that energy transfer is more efficient than suggested by the relation between the critical distance and donor-acceptor distance for elongated peptide conformation.