skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Ultrafast Spectroscopic Investigation of Energy Transfer in Site-Directed Mutants of the Fenna–Matthews–Olson (FMO) Antenna Complex from Chlorobaculum tepidum

Journal Article · · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

Ultrafast transient absorption (TA) and time-resolved fluorescence (TRF) spectroscopic studies were performed on several mutants of the bacteriochlorophyll (BChl) a-containing Fenna–Matthews–Olson (FMO) complex from the green sulfur bacterium Chlorobaculum tepidum. These mutants were generated to perturb a particular BChl a site and determine its effects on the optical spectroscopic properties of the pigment–protein complex. Measurements conducted at 77 K under both oxidizing and reducing conditions revealed changes in the dynamics of the various spectral components as compared to the data set from wild-type FMO. TRF results show that under reducing conditions all FMO samples decay with a similar lifetime in the ~2 ns range. The oxidized samples revealed varying fluorescence lifetimes of the terminal BChl a emitter, considerably shorter than those recorded for the reduced samples, indicating that the quenching mechanism in wild-type FMO is still present in the mutants. Global fitting of TA data yielded similar overall results, and in addition, the lifetimes of early decaying components were determined. Target analyses of TA data for select FMO samples generated kinetic models that better simulate the TA data. Here, a comparison of the lifetime of excitonic components for all samples reveals that the mutations affect mainly the early kinetic components, but not that of the lowest energy exciton, which reflects the flexibility of energy transfer in FMO.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0001035
OSTI ID:
1388221
Journal Information:
Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Vol. 121, Issue 18; Related Information: PARC partners with Washington University in St. Louis (lead); University of California, Riverside; University of Glasgow, UK; Los Alamos National Laboratory; University of New Mexico; New Mexico Corsortium; North Carolina State University; Northwestern University; Oak Ridge National Laboratory; University of Pennsylvania; Sandia National Laboratories; University of Sheffield, UK; ISSN 1520-6106
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 11 works
Citation information provided by
Web of Science

References (44)

A thermophilic green sulfur bacterium from New Zealand hot springs, Chlorobium tepidum sp. nov. journal August 1991
Anoxygenic Photosynthetic Bacteria book January 1995
Chlorosome antenna complexes from green photosynthetic bacteria journal June 2013
Chlorosomes: Structure, Function and Assembly book January 2014
The FMO Protein journal January 2004
Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting journal April 2009
The structural basis for the difference in absorbance spectra for the FMO antenna protein from various green sulfur bacteria journal May 2009
Native Electrospray Mass Spectrometry Reveals the Nature and Stoichiometry of Pigments in the FMO Photosynthetic Antenna Protein journal May 2011
Chemical oxidation of the FMO antenna protein from Chlorobaculum tepidum journal July 2013
Chlorophyll arrangement in a bacteriochlorophyll protein from Chlorobium limicola journal December 1975
VMD: Visual molecular dynamics journal February 1996
Theory of the optical spectra of the bacteriochlorophyll a antenna protein trimer from Prosthecochloris aestuarii journal March 1992
Exciton Simulations of Optical Spectra of the FMO Complex from the Green Sulfur Bacterium Chlorobium tepidum at 6 K journal November 1998
Excited-State Structure and Dynamics in FMO Antenna Complexes from Photosynthetic Green Sulfur Bacteria journal December 1998
Ultrafast Exciton Motion in Photosynthetic Antenna Systems:  The FMO-Complex journal June 1998
The quantitative relationship between structure and polarized spectroscopy in the FMO complex of Prosthecochloris aestuarii: refining experiments and simulations journal January 2002
Exciton Analysis in 2D Electronic Spectroscopy journal June 2005
How Proteins Trigger Excitation Energy Transfer in the FMO Complex of Green Sulfur Bacteria journal October 2006
Computational methodologies and physical insights into electronic energy transfer in photosynthetic light-harvesting complexes journal January 2012
Effect of Spectral Density Shapes on the Excitonic Structure and Dynamics of the Fenna–Matthews–Olson Trimer from Chlorobaculum tepidum journal August 2016
Excited-state absorption in bacteriochlorophyll a-protein from the green photosynthetic bacterium Prosthecochloris aestuarii: reinterpretation of the absorption difference spectrum journal October 1991
Femtosecond energy transfer and spectral equilibration in bacteriochlorophyll a--protein antenna trimers from the green bacterium Chlorobium tepidum journal January 1994
Ultrafast Energy Transfer in FMO Trimers from the Green Bacterium Chlorobium tepidum journal September 1994
Low-temperature energy transfer in FMO trimers from the green photosynthetic bacterium Chlorobium tepidum journal May 1996
Singlet−Singlet Annihilation and Local Heating in FMO Complexes journal January 1996
Ultrafast absorption difference spectra of the Fenna-Matthews-Olson protein at 19 K: experiment and simulations journal January 1997
Exciton Dynamics in FMO Bacteriochlorophyll Protein at Low Temperatures journal September 1997
Pump-probe anisotropies of Fenna-Matthews-Olson protein trimers from Chlorobium tepidum: a diagnostic for exciton localization? journal October 1997
Orientation and excitonic interactions of the Fenna—Matthews—Olson bacteriochlorophyll a protein in membranes of the green sulfur bacterium Chlorobium tepidum journal January 1998
Two-dimensional spectroscopy of electronic couplings in photosynthesis journal March 2005
Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems journal April 2007
Extracting the Excitonic Hamiltonian of the Fenna-Matthews-Olson Complex Using Three-Dimensional Third-Order Electronic Spectroscopy journal April 2011
Intensity Dependence of the Excited State Lifetimes and Triplet Conversion Yield in the Fenna–Matthews–Olson Antenna Protein journal February 2014
Exciton Structure and Energy Transfer in the Fenna–Matthews–Olson Complex journal April 2016
Revisiting the optical properties of the FMO protein journal March 2010
Perturbation of bacteriochlorophyll molecules in Fenna–Matthews–Olson protein complexes through mutagenesis of cysteine residues journal September 2016
Redox effects on the bacteriochlorophyll α-containing Fenna-Matthews-Olson protein fromChlorobium tepidum journal July 1994
Variable fluorescence in green sulfur bacteria journal January 2007
Evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex journal June 2016
Probing the excitonic landscape of the Chlorobaculum tepidum Fenna-Matthews-Olson (FMO) complex: a mutagenesis approach journal April 2017
Low-Temperature Spectroscopic Properties of the Peridinin–Chlorophyll a –Protein (PCP) Complex from the Coral Symbiotic Dinoflagellate Symbiodinium journal April 2013
Spectroscopic studies of two spectral variants of light-harvesting complex 2 (LH2) from the photosynthetic purple sulfur bacterium Allochromatium vinosum journal September 2012
Global and target analysis of time-resolved spectra journal July 2004
Excited State Dynamics in FMO Antenna Complexes from Photosynthetic Green Sulfur Bacteria:  A Kinetic Model journal September 1999

Cited By (2)

Delocalized excitons in natural light-harvesting complexes journal August 2018
Delocalized excitons in natural light harvesting complexes text January 2018