title: Protein matrix elasticity determined by fluorescence anisotropy of its tryptophan residues.
abstract: Rotational motions of Trp residues embedded within human hemoglobin matrix have been measured by using their steady-state fluorescence anisotropy. The mean square angular displacement theta2 of Trp residues, depending on the temperature, can be expressed by W = 1/2Ctheta2 where W is the thermal energy acting on the Trp residues and C the resilient torque constant of the protein matrix. To study the external medium influencing the protein dynamics, comparative experiments were made with protein in aqueous buffer and in the presence of 32% glycerol. The data show that between 5 degrees C and 25 degrees C, external medium acts on the protein matrix elasticity.
authors.affiliation: Laboratoire de Physicochimie Biomoléculaire et Cellulaire, Université Pierre et Marie Curie, Paris, France. czentz@lpbc.jussieu.fr
authors.forename: Christian
authors.initials: C
authors.lastname: Zentz
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Glandières
authors.forename: Sadok
authors.initials: S
authors.lastname: El Moshni
authors.forename: Bernard
authors.initials: B
authors.lastname: Alpert
mesh_terms: D004548:Elasticity; D005454:Fluorescence Polarization; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry*; D013696:Temperature; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D006454:Hemoglobins; D011506:Proteins; D014364:Tryptophan