title: On destabilization of the Fenna-Matthews-Olson complex of Chlorobaculum tepidum.
abstract: The Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Chlorobaculum tepidum was studied with respect to its stability. We provide a critical assessment of published and recently measured optical spectra. FMO complexes were found to destabilize over time producing spectral shifts, with destabilized samples having significantly higher hole-burning efficiencies; indicating a remodeled protein energy landscape. Observed correlated peak shifts near 825 and 815 nm suggest possible correlated (protein) fluctuations. It is proposed that the value of 35 cm(-1) widely used for reorganization energy (E λ ), which has important implications for the contributions to the coherence rate (Kreisbeck and Kramer 3:2828-2833, 2012), in various modeling studies of two-dimensional electronic spectra is overestimated. We demonstrate that the value of E λ is most likely about 15-22 cm(-1) and suggest that spectra reported in the literature (often measured on different FMO samples) exhibit varied peak positions due to different purification/isolation procedures or destabilization effects.
authors.affiliation: Department of Chemistry, Kansas State University, Manhattan, KS, 66506, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Kell
authors.forename: Khem
authors.initials: K
authors.lastname: Acharya
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
authors.forename: Ryszard
authors.initials: R
authors.lastname: Jankowiak
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D019414:Chlorobi / Q000378:metabolism*; D004735:Energy Transfer; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry / Q000378:metabolism*; D013057:Spectrum Analysis
chemical_list: D001426:Bacterial Proteins; C086320:FMO bacteriochlorophyll protein, Bacteria; D045342:Light-Harvesting Protein Complexes