The dynamical transition in proteins of bacterial photosynthetic reaction centers observed by echo-detected EPR of specific spin labels
- 39 Downloads
An echo-detected electron paramagnetic resonance (ED EPR) approach was used to study molecular dynamics in photosynthetic reaction centers (RCs) fromRhodobacter sphaeroides R26, employing the specific spin label methanethiosulfonate and 3-maliemido proxyl. ED EPR has recently been shown to be sensitive to so-called dynamical transition in disordered media, which is characterized by the transition from a harmonic-like librational motion of a molecule to an anharmonic one or to a stochastic wobbling motion. ED EPR line shapes studied over a wide temperature range reveal a sharp transition occurring above 180 K. The possible relation of the found transition to the temperature dependence of electron transfer reactions in RC is discussed.
KeywordsDynamical Transition Spin Label Methanethiosulfonate Anisotropic Relaxation Bacterial Photosynthetic Reaction Center
Unable to display preview. Download preview PDF.
- 13.Feher G., Okamura M.Y., Kleinfeld D. in: Protein Structure: Molecular and Electronic Reactivity (Austin R., Buhks E., Chance B., De Vault D., Dutton P.L., Frauenfelder H., Goldanskii V.I. eds.), pp. 399–421. New York: Springer 1987.Google Scholar
- 20.Feher G., Okamura M.Y. (eds.): The Photosynthetic Bacteria, pp. 349–386. New York: Plenum Press 1978.Google Scholar
- 23.Dzuba S.A., Maryasov A.G., Salikhov K.M., Tsvetkov Yu.D.: J. Magn. Reson.58, 95–117 (1984)Google Scholar