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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
Title:Spectral hole burning, recovery, and thermocycling in chlorophyll-protein complexes: distributions of barriers on the protein energy landscape.
Authors:Najafi M,  Herascu N,  Seibert M,  Picorel R,  Jankowiak R,  Zazubovich V
Link:https://www.ncbi.nlm.nih.gov/pubmed/22957798?dopt=Abstract
Category:J Phys Chem B
PMID:22957798
Dept Affiliation: PHYSICS
1 Department of Physics, Concordia University, 7141 Sherbrooke Str. West, Montreal, Quebec H4B 1R6 Canada.

Description:

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

J Phys Chem B. 2012 Sep 27;116(38):11780-90

Authors: Najafi M, Herascu N, Seibert M, Picorel R, Jankowiak R, Zazubovich V

Abstract

Chlorophyll-protein complexes are ideal model systems for protein energy landscape research. Here pigments, used in optical spectroscopy experiments as sensitive probes to local dynamics, are built into protein by Nature (in a large variety of local environments; without extraneous chemical manipulations or genetic engineering). Distributions of the tunneling parameter, ?, and/or protein energy landscape barrier heights, V, have been determined for (the lowest energy state of) the CP43 core antenna complex of photosystem II. We demonstrate that spectral hole burning (SHB) and hole recovery (HR) measurements are capable of delivering important information on protein energy landscape properties and spectral diffusion mechanism details. In particular, we show that tunneling rather than barrier hopping is responsible for both persistent SHB and subsequent HR at 5-12 K, which allows us to estimate the md(2) parameter of the tunneling entities as ~1.0 × 10(-46) kg·m(2). The subdistributions of ? actually contributing to the nonsaturated spectral holes (and affecting their recovery) differ from the respective full true distributions. In the case of the full ?-distribution being uniform (or the barrier height distribution ~1/vV, a model which has been widely employed in theories of amorphous solids at low temperatures and in HR analysis), the difference is qualitative, with ? subdistributions probed in the HR experiments being highly asymmetrical, and barrier V subdistributions deviating significantly from ~1/vV. Thus, the distribution of ? for the protein energy landscape tier directly probed by SHB is likely Gaussian and not uniform. Additionally, a Gaussian distribution of barriers, with parameters incompatible with those of the landscape tier directly probed by SHB, contributes to the thermocycling results.

PMID: 22957798 [PubMed - indexed for MEDLINE]