title: HemX is required for production of 2-ketogluconate, the predominant organic anion required for inorganic phosphate solubilization by Burkholderia sp. Ha185.
abstract: The bacterium Burkholderia sp. Ha185 readily solubilizes inorganic phosphate by releasing the low molecular weight organic anion, 2-ketogluconate. Using random transposon mutagenesis and in silico analysis, a mutation that caused almost complete abolition of phosphate solubilization was located within hemX, which is part of the hem operon. Burkholderia sp. Ha185 HemX is a multidomain protein, predicted to encode a bifunctional uroporphyrinogen-III synthetase/uroporphyrin-III C-methyltransferase, which has not previously been implicated in phosphate solubilization. Complementation of hemX restored the ability of the mutant to solubilize phosphate in both plate and liquid cultures. Based on a combination of organic-anion profiling, quantitative polymerase chain reaction and in silico analyses, hemX was confirmed to be solely responsible for hydroxyapatite solubilization in Burkholderia sp. Ha185. It is proposed that the biosynthesis of a yet to be determined redox cofactor by HemX is the main pathway for generating 2-ketogluconate via a haem-dependent gluconate 2-dehydrogenase in Burkholderia sp. Ha185.
authors.affiliation: Innovative Farm Systems, AgResearch Limited, Christchurch, New Zealand.|Soil Biology, Bio-Protection Research Centre, Lincoln University, Christchurch, New Zealand.
authors.forename: Pei-Chun Lisa
authors.initials: PC
authors.lastname: Hsu
authors.affiliation: Soil Biology, Bio-Protection Research Centre, Lincoln University, Christchurch, New Zealand.
authors.forename: Leo
authors.initials: L
authors.lastname: Condron
authors.affiliation: Innovative Farm Systems, AgResearch Limited, Christchurch, New Zealand.|Soil Biology, Bio-Protection Research Centre, Lincoln University, Christchurch, New Zealand.
authors.forename: Maureen
authors.initials: M
authors.lastname: O'Callaghan
authors.affiliation: Innovative Farm Systems, AgResearch Limited, Christchurch, New Zealand.|Soil Biology, Bio-Protection Research Centre, Lincoln University, Christchurch, New Zealand.
authors.forename: Mark R H
authors.initials: MR
authors.lastname: Hurst
mesh_terms: D019117:Burkholderia / Q000235:genetics* / Q000378:metabolism*; D002237:Carbohydrate Dehydrogenases; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D005942:Gluconates / Q000378:metabolism*; D011163:Hydroxymethylbilane Synthase / Q000235:genetics; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D009154:Mutation; D009876:Operon; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism*; D012995:Solubility
chemical_list: D005942:Gluconates; D010710:Phosphates; C008229:2-ketogluconate; D002237:Carbohydrate Dehydrogenases; C020577:gluconate 2-dehydrogenase; D011163:Hydroxymethylbilane Synthase