title: Autotrophic methanotrophy in verrucomicrobia: Methylacidiphilum fumariolicum SolV uses the Calvin-Benson-Bassham cycle for carbon dioxide fixation.
abstract: Genome data of the extreme acidophilic verrucomicrobial methanotroph Methylacidiphilum fumariolicumstrain SolV indicated the ability of autotrophic growth. This was further validated by transcriptome analysis, which showed that all genes required for a functional Calvin-Benson-Bassham (CBB) cycle were transcribed. Experiments with (13)CH(4) or (13)CO(2) in batch and chemostat cultures demonstrated that CO(2) is the sole carbon source for growth of strain SolV. In the presence of CH(4), CO(2) concentrations in the headspace below 1% (vol/vol) were growth limiting, and no growth was observed when CO(2)concentrations were below 0.3% (vol/vol). The activity of the key enzyme of the CBB cycle, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), measured with a (13)C stable-isotope method was about 70 nmol CO(2) fixed · min(-1)· mg of protein(-1). An immune reaction with antibody against the large subunit of RuBisCO on Western blots was found only in the supernatant fractions of cell extracts. The apparent native mass of the RuBisCO complex in strain SolV was about 482 kDa, probably consisting of 8 large (53-kDa) and 8 small (16-kDa) subunits. Based on phylogenetic analysis of the corresponding RuBisCO gene, we postulate that RuBisCO of the verrucomicrobial methanotrophs represents a new type of form I RuBisCO.
authors: Department of Microbiology, IWWR, Radboud University Nijmegen, Heyendaalseweg 135, NL-6525 AJ, Nijmegen, the Netherlands.
authors: Ahmad F
authors: AF
authors: Khadem
authors: Arjan
authors: A
authors: Pol
authors: Adam
authors: A
authors: Wieczorek
authors: Seyed S
authors: SS
authors: Mohammadi
authors: Kees-Jan
authors: KJ
authors: Francoijs
authors: Henk G
authors: HG
authors: Stunnenberg
authors: Mike S M
authors: MS
authors: Jetten
authors: Huub J M
authors: HJ
authors: Op den Camp
mesh_terms: D052818:Autotrophic Processes; D001419:Bacteria / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D015151:Immunoblotting; D010788:Photosynthesis; D010802:Phylogeny; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002245:Carbon Dioxide; D002244:Carbon; D012273:Ribulose-Bisphosphate Carboxylase