title: Native FMO-reaction center supercomplex in green sulfur bacteria: an electron microscopy study.
abstract: Chlorobaculum tepidum is a representative of green sulfur bacteria, a group of anoxygenic photoautotrophs that employ chlorosomes as the main light-harvesting structures. Chlorosomes are coupled to a ferredoxin-reducing reaction center by means of the Fenna-Matthews-Olson (FMO) protein. While the biochemical properties and physical functioning of all the individual components of this photosynthetic machinery are quite well understood, the native architecture of the photosynthetic supercomplexes is not. Here we report observations of membrane-bound FMO and the analysis of the respective FMO-reaction center complex. We propose the existence of a supercomplex formed by two reaction centers and four FMO trimers based on the single-particle analysis of the complexes attached to native membrane. Moreover, the structure of the photosynthetic unit comprising the chlorosome with the associated pool of RC-FMO supercomplexes is proposed.
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic. bina@umbr.cas.cz.|Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic. bina@umbr.cas.cz.
authors.forename: David
authors.initials: D
authors.lastname: Bína
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic.|Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic.
authors.forename: Zdenko
authors.initials: Z
authors.lastname: Gardian
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic.|Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic.
authors.forename: František
authors.initials: F
authors.lastname: Vácha
authors.affiliation: Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic.|Institute of Plant Molecular Biology, Biology Centre CAS, Branišovská 31, 370 05, České Budějovice, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Litvín
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D019414:Chlorobi / Q000737:chemistry*; D003593:Cytoplasm / Q000737:chemistry; D007425:Intracellular Membranes / Q000737:chemistry; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C086320:FMO bacteriochlorophyll protein, Bacteria; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins
keywords: Chlorosome; Electron microscopy; FMO (Fenna–Matthews–Olson protein); Green sulfur bacteria; Light-harvesting complex; Reaction center