title: Room temperature phosphorescence study on the structural flexibility of single tryptophan containing proteins.
abstract: In this study, we have undertaken efforts to find correlation between phosphorescence lifetimes of single tryptophan containing proteins and some structural indicators of protein flexibility/rigidity, such as the degree of tryptophan burial or its exposure to solvent, protein secondary and tertiary structure of the region of localization of tryptophan as well as B factors for tryptophan residue and its immediate surroundings. Bearing in mind that, apart from effective local viscosity of the protein/solvent matrix, the other factor that concur in determining room temperature tryptophan phosphorescence (RTTP) lifetime in proteins is the extent of intramolecular quenching by His, Cys, Tyr and Trp side chains, the crystallographic structures derived from the Brookhaven Protein Data Bank were also analyzed concentrating on the presence of potentially quenching amino acid side chains in the close proximity of the indole chromophore. The obtained results indicated that, in most cases, the phosphorescence lifetimes of tryptophan containing proteins studied tend to correlate with the above mentioned structural indicators of protein rigidity/flexibility. This correlation is expected to provide guidelines for the future development of phosphorescence lifetime-based method for the prediction of structural flexibility of proteins, which is directly linked to their biological function.
authors.affiliation: Institute of General Food Chemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, ul. Stefanowskiego 4/10, 90-924 Lodz, Poland. Electronic address: agnieszka.kowalska-baron@p.lodz.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kowalska-Baron
authors.affiliation: Institute of General Food Chemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, ul. Stefanowskiego 4/10, 90-924 Lodz, Poland.
authors.forename: Krystian
authors.initials: K
authors.lastname: Gałęcki
authors.affiliation: Institute of General Food Chemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, ul. Stefanowskiego 4/10, 90-924 Lodz, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Wysocki
mesh_terms: D030562:Databases, Protein; D008163:Luminescent Measurements; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D011506:Proteins; D014364:Tryptophan
keywords: Phosphorescence lifetime; Protein flexibility; Temperature factors; Tryptophan containing proteins