title: Photophysical properties of the excited states of bacteriochlorophyll f in solvents and in chlorosomes.
abstract: Bacteriochlorophyll f (BChl f) is a photosynthetic pigment predicted nearly 40 years ago as a fourth potential member of the Chlorobium chlorophyll family (BChl c, d, and e). However, this pigment still has not been found in a naturally occurring organism. BChl c, d, and e are utilized by anoxygenic green photosynthetic bacteria for assembly of chlorosomes--large light-harvesting complexes that allow those organisms to survive in habitats with extremely low light intensities. Recently, using genetic methods on two different strains of Chlorobaculum limnaeum that naturally produce BChl e, two research groups produced mutants that synthesize BChl f and assemble it into chlorosomes. In this study, we present detailed investigations on spectral and dynamic characteristics of singlet excited and triplet states of BChl f with the application of ultrafast time-resolved absorption and fluorescence spectroscopies. The studies were performed on isolated BChl f in various solvents, at different temperatures, and on BChl f-containing chlorosomes in order to uncover any unusual or unfavorable properties that stand behind the lack of appearance of this pigment in natural environments.
authors.affiliation: Photosynthetic Antenna Research Center, ‡Departments of Biology and Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.
authors.forename: Dariusz M
authors.initials: DM
authors.lastname: Niedzwiedzki
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Orf
authors.forename: Marcus
authors.initials: M
authors.lastname: Tank
authors.forename: Kajetan
authors.initials: K
authors.lastname: Vogl
authors.forename: Donald A
authors.initials: DA
authors.lastname: Bryant
authors.forename: Robert E
authors.initials: RE
authors.lastname: Blankenship
mesh_terms: D001429:Bacteriochlorophylls / Q000737:chemistry* / Q000302:isolation & purification; D041883:Chlorobium / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010782:Photolysis; D011725:Pyridines / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D001429:Bacteriochlorophylls; D011725:Pyridines; D012997:Solvents; C120931:bacteriochlorophyll f; C023666:pyridine