title: Structural characterization of NDH-1 complexes of Thermosynechococcus elongatus by single particle electron microscopy.
abstract: The structure of the multifunctional NAD(P)H dehydrogenase type 1 (NDH-1) complexes from cyanobacteria was investigated by growing the wild type and specific ndh His-tag mutants of Thermosynechococcus elongatus BP-1 under different CO(2) conditions, followed by an electron microscopy (EM) analysis of their purified membrane protein complexes. Single particle averaging showed that the complete NDH-1 complex (NDH-1L) is L-shaped, with a relatively short hydrophilic arm. Two smaller complexes were observed, differing only at the tip of the membrane-embedded arm. The smallest one is considered to be similar to NDH-1M, lacking the NdhD1 and NdhF1 subunits. The other fragment, named NDH-1I, is intermediate between NDH-1L and NDH-1M and only lacks a mass compatible with the size of the NdhF1 subunit. Both smaller complexes were observed under low- and high-CO(2) growth conditions, but were much more abundant under the latter conditions. EM characterization of cyanobacterial NDH-1 further showed small numbers of NDH-1 complexes with additional masses. One type of particle has a much longer peripheral arm, similar to the one of NADH: ubiquinone oxidoreductase (complex I) in E. coli and other organisms. This indicates that Thermosynechococcus elongatus must have protein(s) which are structurally homologous to the E. coli NuoE, -F, and -G subunits. Another low-abundance type of particle (NDH-1U) has a second labile hydrophilic arm at the tip of the membrane-embedded arm. This U-shaped particle has not been observed before by EM in a NDH-I preparation.
authors.affiliation: Department of Biophysical Chemistry, GBB, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Ana A
authors.initials: AA
authors.lastname: Arteni
authors.forename: Pengpeng
authors.initials: P
authors.lastname: Zhang
authors.forename: Natalia
authors.initials: N
authors.lastname: Battchikova
authors.forename: Teruo
authors.initials: T
authors.lastname: Ogawa
authors.forename: Eva-Mari
authors.initials: EM
authors.lastname: Aro
authors.forename: Egbert J
authors.initials: EJ
authors.lastname: Boekema
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D001671:Biochemistry / Q000379:methods; D002245:Carbon Dioxide / Q000737:chemistry; D002846:Chromatography, Affinity; D000458:Cyanobacteria / Q000201:enzymology*; D003902:Detergents / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism; D005821:Genetic Techniques; D008854:Microscopy, Electron / Q000379:methods; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000737:chemistry* / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000737:chemistry; D009532:Nickel / Q000737:chemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry; D020524:Thylakoids / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D003902:Detergents; D045322:Photosynthetic Reaction Center Complex Proteins; D002245:Carbon Dioxide; D009532:Nickel; D016660:NAD(P)H Dehydrogenase (Quinone); C081468:NdhF protein, bacteria; D009245:NADH Dehydrogenase