title: Temperature dependence of protein fluorescence in Rb. sphaeroides reaction centers frozen to 80 K in the dark or on the actinic light as the indicator of protein conformational dynamics.
abstract: The differences in the average fluorescence lifetime (τav) of tryptophanyls in photosynthetic reaction center (RC) of the purple bacteria Rb. sphaeroides frozen to 80 K in the dark or on the actinic light was found. This difference disappeared during subsequent heating at the temperatures above 250 K. The computer-based calculation of vibration spectra of the tryptophan molecule was performed. As a result, the normal vibrational modes associated with deformational vibrations of the aromatic ring of the tryptophan molecule were found. These deformational vibrations may be active during the nonradiative transition of the molecule from the excited to the ground state. We assume that the differences in τav may be associated with the change in the activity of these vibration modes due to local variations in the microenvironment of tryptophanyls during the light activation.
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia. knox@biophys.msu.ru.
authors.forename: P P
authors.initials: PP
authors.lastname: Knox
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia.
authors.forename: B N
authors.initials: BN
authors.lastname: Korvatovsky
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia.
authors.forename: P M
authors.initials: PM
authors.lastname: Krasilnikov
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia.
authors.forename: V Z
authors.initials: VZ
authors.lastname: Paschenko
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia.
authors.forename: N H
authors.initials: NH
authors.lastname: Seifullina
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia.
authors.forename: N P
authors.initials: NP
authors.lastname: Grishanova
authors.affiliation: Biological Faculty, Moscow State University, Moscow, 119991, Russia.
authors.forename: A B
authors.initials: AB
authors.lastname: Rubin
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D005453:Fluorescence; D005990:Glycerol / Q000737:chemistry; D008958:Models, Molecular; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D013696:Temperature; D014364:Tryptophan / Q000737:chemistry; D014732:Vibration; D014867:Water / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D014867:Water; D014364:Tryptophan; D005990:Glycerol