title: Investigation of spectral diffusion in ribonuclease by photolabeling of intrinsic aromatic amino acids.
abstract: Spectral diffusion dynamics in ribonuclease A was observed via the broadening of photochemical holes burned into the absorption spectrum of intrinsic tyrosine residues. Unlike previous results based on hole burning of chromophores in the pockets of heme proteins, where spectral diffusion develops according to a power law in time, the dynamics in ribonuclease follow a logarithmic law. The results suggest that the experiment preferentially labels the tyrosines located on the surface of the protein where the two-level system dynamics of the glass host matrix exert a strong influence.
authors.affiliation: E14 and Lehrstuhl für Physik Weihenstephan, Physics Department, Technische Universität München, 85350 Freising, Germany. mark.somoza@physik.blm.tu-muenchen.de
authors.forename: Mark M
authors.initials: MM
authors.lastname: Somoza
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Ponkratov
authors.forename: Josef
authors.initials: J
authors.lastname: Friedrich
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D004058:Diffusion; D008027:Light; D008956:Models, Chemical; D011487:Protein Conformation; D012259:Ribonuclease, Pancreatic / Q000737:chemistry*; D013194:Staining and Labeling; D013816:Thermodynamics; D014443:Tyrosine / Q000737:chemistry
chemical_list: D024322:Amino Acids, Aromatic; D014443:Tyrosine; D012259:Ribonuclease, Pancreatic