title: Optically detected magnetic resonance study of tyrosine residues in point-mutated bacteriophage T4 lysozyme.
abstract: Two spectroscopically distinct types of tyrosine (Tyr) residues in triply point mutated bacteriophage T4 lysozyme, which contains no tryptophan (Trp), have been detected by optical detection of triplet-state magnetic resonance (ODMR) spectroscopy. Their triplet states are characterized by similar E but different D values. The Tyr site which exhibits the lower D value and has the red-shifted phosphorescence origin is quenched by energy transfer to Trp and has D and E values comparable to previously studied Tyr residues. The blue-shifted Tyr site, which is not quenched by Trp, exhibits a larger D value that has been found previously. Calculation of energy-transfer efficiencies of Tyr-Trp pairs based on the crystal structure of the native enzyme provides a possible assignment of Tyr sites to the two different spectral types.
authors.affiliation: Department of Chemistry, University of California, Davis 95616.
authors.forename: S
authors.initials: S
authors.lastname: Ghosh
authors.forename: L H
authors.initials: LH
authors.lastname: Zang
authors.forename: A H
authors.initials: AH
authors.lastname: Maki
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D009113:Muramidase / Q000235:genetics; D009154:Mutation; D013604:T-Phages / Q000201:enzymology* / Q000235:genetics; D014443:Tyrosine
chemical_list: D014443:Tyrosine; D009113:Muramidase