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Low-temperature protein dynamics of the B800 molecules in the LH2 light-harvesting complex: spectral hole burning study and comparison with single photosynthetic complex spectroscopy.

Author(s): Grozdanov D, Herascu N, Reinot T, Jankowiak R, Zazubovich V

J Phys Chem B. 2010 Mar 18;114(10):3426-38 Authors: Grozdanov D, Herascu N, Reinot T, Jankowiak R, Zazubovich V

Article GUID: 20166717
Parameters of the protein energy landscapes of several light-harvesting complexes probed via spectral hole growth kinetics measurements.

Author(s): Herascu N, Najafi M, Amunts A, Pieper J, Irrgang KD, Picorel R, Seibert M, Zazubovich V

J Phys Chem B. 2011 Mar 31;115(12):2737-47 Authors: Herascu N, Najafi M, Amunts A, Pieper J, Irrgang KD, Picorel R, Seibert M, Zazubovich V

Article GUID: 21391534
Effects of the distributions of energy or charge transfer rates on spectral hole burning in pigment-protein complexes at low temperatures.

Author(s): Herascu N, Ahmouda S, Picorel R, Seibert M, Jankowiak R, Zazubovich V

J Phys Chem B. 2011 Dec 22;115(50):15098-109 Authors: Herascu N, Ahmouda S, Picorel R, Seibert M, Jankowiak R, Zazubovich V

Article GUID: 22046956
Spectral hole burning, recovery, and thermocycling in chlorophyll-protein complexes: distributions of barriers on the protein energy landscape.

Author(s): Najafi M, Herascu N, Seibert M, Picorel R, Jankowiak R, Zazubovich V

J Phys Chem B. 2012 Sep 27;116(38):11780-90 Authors: Najafi M, Herascu N, Seibert M, Picorel R, Jankowiak R, Zazubovich V

Article GUID: 22957798
Modeling of various optical spectra in the presence of slow excitation energy transfer in dimers and trimers with weak interpigment coupling: FMO as an example.

Author(s): Herascu N, Kell A, Acharya K, Jankowiak R, Blankenship RE, Zazubovich V

J Phys Chem B. 2014 Feb 27;118(8):2032-40 Authors: Herascu N, Kell A, Acharya K, Jankowiak R, Blankenship RE, Zazubovich V

Article GUID: 24506338
Conformational Changes in Pigment-Protein Complexes at Low Temperatures-Spectral Memory and a Possibility of Cooperative Effects.

Author(s): Najafi M, Herascu N, Shafiei G, Picorel R, Zazubovich V

J Phys Chem B. 2015 Jun 11;119(23):6930-40 Authors: Najafi M, Herascu N, Shafiei G, Picorel R, Zazubovich V

Article GUID: 25985255
Spectral Hole Burning in Cyanobacterial Photosystem I with P700 in Oxidized and Neutral States.

Author(s): Herascu N, Hunter MS, Shafiei G, Najafi M, Johnson TW, Fromme P, Zazubovich V

J Phys Chem B. 2016;120(40):10483-10495 Authors: Herascu N, Hunter MS, Shafiei G, Najafi M, Johnson TW, Fromme P, Zazubovich V

Article GUID: 27661089
Title:Conformational Changes in Pigment-Protein Complexes at Low Temperatures-Spectral Memory and a Possibility of Cooperative Effects.
Authors:Najafi M,  Herascu N,  Shafiei G,  Picorel R,  Zazubovich V
Link:https://www.ncbi.nlm.nih.gov/pubmed/25985255?dopt=Abstract
Category:J Phys Chem B
PMID:25985255
Dept Affiliation: PHYSICS
1 †Department of Physics, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
2 ‡Estacion Experimental de Aula Dei (CSIC), Avda. Montañana 1005, 50059 Zaragoza, Spain.

Description:

Conformational Changes in Pigment-Protein Complexes at Low Temperatures-Spectral Memory and a Possibility of Cooperative Effects.

J Phys Chem B. 2015 Jun 11;119(23):6930-40

Authors: Najafi M, Herascu N, Shafiei G, Picorel R, Zazubovich V

Abstract

We employed nonphotochemical hole burning (NPHB) and fluorescence line narrowing (FLN) spectroscopies to explore protein energy landscapes and energy transfer processes in dimeric Cytochrome b6f, containing one chlorophyll molecule per protein monomer. The parameters of the energy landscape barrier distributions quantitatively agree with those reported for other pigment-protein complexes involved in photosynthesis. Qualitatively, the distributions of barriers between protein substates involved in the light-induced conformational changes (i.e., -NPHB) are close to glass-like ~1/vV (V is the barrier height) and not to Gaussian. There is a high degree of correlation between the heights of the barriers in the ground and excited states in individual pigment-protein systems, as well as nearly perfect spectral memory. Both NPHB and hole recovery are due to phonon-assisted tunneling associated with the increase of the energy of a scattered phonon. As the latter is unlikely for simultaneously both the hole burning and the hole recovery, proteins must exhibit a NPHB mechanism involving diffusion of the free volume toward the pigment. Entities involved in the light-induced conformational changes are characterized by md(2) value of about 1.0 × 10(-46) kg·m(2). Thus, these entities are protons or, alternatively, small groups of atoms experiencing sub-Å shifts. However, explaining all spectral hole burning and recovery data simultaneously, employing just one barrier distribution, requires a drastic decrease in the attempt frequency to about 100 MHz. This decrease may occur due to cooperative effects. Evidence is presented for excitation energy transfer between the chlorophyll molecules of the adjacent monomers. The magnitude of the dipole-dipole coupling deduced from the ?-FLN spectra is in good agreement with the structural data, indicating that the explored protein was intact.

PMID: 25985255 [PubMed - indexed for MEDLINE]