title: Proximity relations between tyrosine and tryptophan residues in fd phage determined by luminescence measurements.
abstract: Resonance energy transfer from tyrosine to tryptophan residues was detected in the phage fd. The magnitude of the transfer efficiency was estimated by both a traditional and an alternative method. The latter involved comparison of the indole acceptor excitation spectrum full-width half-maximum with a set of standard values differing in the amount of absorbance contributed by tyrosine donor. Both methods lead to the same conclusion: essentially all the tyrosine residues of the viral coat are within 0.9 nm of a tryptophan residue. Also, fluorescence lifetime measurements provide additional support for the hypothesis that there are at least two different environments for the coat protein's sole indole side-chain. Little if any DNA phosphorescence was seen, consistent with the nucleic acid bases being stacked in the DNA core.
mesh_terms: D003090:Coliphages / Q000032:analysis*; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000032:analysis*; D014443:Tyrosine / Q000032:analysis*; D014764:Viral Proteins / Q000032:analysis*
chemical_list: D014764:Viral Proteins; D014443:Tyrosine; D014364:Tryptophan