title: The stoichiometry of the chloroplast ATP synthase oligomer III in Chlamydomonas reinhardtii is not affected by the metabolic state.
abstract: The chloroplast H(+)-ATP synthase is a key component for the energy supply of higher plants and green algae. An oligomer of identical protein subunits III is responsible for the conversion of an electrochemical proton gradient into rotational motion. It is highly controversial if the oligomer III stoichiometry is affected by the metabolic state of any organism. Here, the intact oligomer III of the ATP synthase from Chlamydomonas reinhardtii has been isolated for the first time. Due to the importance of the subunit III stoichiometry for energy conversion, a gradient gel system was established to distinguish oligomers with different stoichiometries. With this methodology, a possible alterability of the stoichiometry in respect to the metabolic state of the cells was examined. Several growth parameters, i.e., light intensity, pH value, carbon source, and CO(2) concentration, were varied to determine their effects on the stoichiometry. Contrary to previous suggestions for E. coli, the oligomer III of the chloroplast H(+)-ATP synthase always consists of a constant number of monomers over a wide range of metabolic states. Furthermore, mass spectrometry indicates that subunit III from C. reinhardtii is not modified posttranslationally. Data suggest a subunit III stoichiometry of the algae ATP synthase divergent from higher plants.
authors.affiliation: Department of Chemistry, Physical Biochemistry, Darmstadt University of Technology, Petersenstrasse 22, D-64287 Darmstadt, Germany.
authors.forename: Jürgen M W
authors.initials: JM
authors.lastname: Meyer Zu Tittingdorf
authors.forename: Sascha
authors.initials: S
authors.lastname: Rexroth
authors.forename: Eva
authors.initials: E
authors.lastname: Schäfer
authors.forename: Ralf
authors.initials: R
authors.lastname: Schlichting
authors.forename: Christoph
authors.initials: C
authors.lastname: Giersch
authors.forename: Norbert A
authors.initials: NA
authors.lastname: Dencher
authors.forename: Holger
authors.initials: H
authors.lastname: Seelert
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000201:enzymology*; D025222:Chloroplast Proton-Translocating ATPases / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry*; D019281:Dimerization; D004734:Energy Metabolism / Q000502:physiology*; D007527:Isoenzymes / Q000096:biosynthesis / Q000737:chemistry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D046912:Multiprotein Complexes; D025222:Chloroplast Proton-Translocating ATPases