title: The structure of FCPb, a light-harvesting complex in the diatom Cyclotella meneghiniana.
abstract: Diatoms possess fucoxanthin chlorophyll proteins (FCP) as light-harvesting systems. These membrane intrinsic proteins bind fucoxanthin as major carotenoid and Chl c as accessory chlorophyll. The relatively high sequence homology to higher plant light-harvesting complex II gave rise to the assumption of a similar overall structure. From centric diatoms like Cyclotella meneghiniana, however, two major FCP complexes can be isolated. FCPa, composed of Fcp2 and Fcp6 subunits, was demonstrated to be trimeric, whereas FCPb, known to contain Fcp5 polypeptides, is of higher oligomeric state. No molecular structure of either complex is available so far. Here we used electron microscopy and single particle analysis to elucidate the overall architecture of FCPb. The complexes are built from trimers as basic unit, assembling into nonameric moieties. The trimer itself is smaller, i.e. more compact than LHCII, but the main structural features are conserved.
authors.affiliation: Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Röding
authors.affiliation: Department of Electron Microscopy, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
authors.forename: Egbert
authors.initials: E
authors.lastname: Boekema
authors.affiliation: Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany. C.Buechel@bio.uni-frankfurt.de.
authors.forename: Claudia
authors.initials: C
authors.lastname: Büchel
mesh_terms: D061146:Chlorophyll Binding Proteins / Q000737:chemistry* / Q000648:ultrastructure; D002850:Chromatography, Gel; D017377:Diatoms / Q000378:metabolism*; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000648:ultrastructure; D055503:Protein Multimerization
chemical_list: D061146:Chlorophyll Binding Proteins; D045342:Light-Harvesting Protein Complexes
keywords: Electron microscopy; Fucoxanthin chlorophyll protein; Oligomeric state; Single particle analysis