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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
On the Controversial Nature of the 825 nm Exciton Band in the FMO Protein Complex.

Author(s): Kell A, Acharya K, Zazubovich V, Jankowiak R

J Phys Chem Lett. 2014 Apr 17;5(8):1450-6 Authors: Kell A, Acharya K, Zazubovich V, Jankowiak R

Article GUID: 26269993
On the Conflicting Estimations of Pigment Site Energies in Photosynthetic Complexes: A Case Study of the CP47 Complex.

Author(s): Reinot T, Chen J, Kell A, Jassas M, Robben KC, Zazubovich V, Jankowiak R

Anal Chem Insights. 2016;11:35-48 Authors: Reinot T, Chen J, Kell A, Jassas M, Robben KC, Zazubovich V, Jankowiak R

Article GUID: 27279733
Title:On the Conflicting Estimations of Pigment Site Energies in Photosynthetic Complexes: A Case Study of the CP47 Complex.
Authors:Reinot T,  Chen J,  Kell A,  Jassas M,  Robben KC,  Zazubovich V,  Jankowiak R
Link:https://www.ncbi.nlm.nih.gov/pubmed/27279733?dopt=Abstract
Category:Anal Chem Insights
PMID:27279733
Dept Affiliation: PHYSICS
1 Department of Chemistry, Kansas State University, Manhattan, KS, USA.
2 Department of Physics, Concordia University, Montreal, QC, Canada.
3 Department of Chemistry, Kansas State University, Manhattan, KS, USA.; Department of Physics, Kansas State University, Manhattan, KS, USA.

Description:

On the Conflicting Estimations of Pigment Site Energies in Photosynthetic Complexes: A Case Study of the CP47 Complex.

Anal Chem Insights. 2016;11:35-48

Authors: Reinot T, Chen J, Kell A, Jassas M, Robben KC, Zazubovich V, Jankowiak R

Abstract

We focus on problems with elucidation of site energies [Formula: see text] for photosynthetic complexes (PSCs) in order to raise some genuine concern regarding the conflicting estimations propagating in the literature. As an example, we provide a stern assessment of the site energies extracted from fits to optical spectra of the widely studied CP47 antenna complex of photosystem II from spinach, though many general comments apply to other PSCs as well. Correct values of [Formula: see text] for chlorophyll (Chl) a in CP47 are essential for understanding its excitonic structure, population dynamics, and excitation energy pathway(s). To demonstrate this, we present a case study where simultaneous fits of multiple spectra (absorption, emission, circular dichroism, and nonresonant hole-burned spectra) show that several sets of parameters can fit the spectra very well. Importantly, we show that variable emission maxima (690-695 nm) and sample-dependent bleaching in nonresonant hole-burning spectra reported in literature could be explained, assuming that many previously studied CP47 samples were a mixture of intact and destabilized proteins. It appears that the destabilized subpopulation of CP47 complexes could feature a weakened hydrogen bond between the 13(1)-keto group of Chl29 and the PsbH protein subunit, though other possibilities cannot be entirely excluded, as discussed in this work. Possible implications of our findings are briefly discussed.

PMID: 27279733 [PubMed]