The flavoprotein SoxF functions in chemotrophic thiosulfate oxidation of Paracoccus pantotrophus in vivo and in vitro.
Paracoccus pantotrophus strain GBsoxFDelta carries a deletion in the soxF gene that inactivates flavoprotein SoxF-sulfide dehydrogenase. This strain grew with thiosulfate slower than the wild type. GBsoxFDelta cells oxidized thiosulfate at a rate of 40% and hydrogen sulfide at a rate of 45% of the wild type. Complementation of GBsoxFDelta with plasmid pRIsoxF carrying the soxF gene increased these rates to 83% and 70%, respectively. However, GBsoxFDelta and GBsoxFDelta (pRIsoxF) oxidized thiosulfate and hydrogen sulfide to sulfate as evident from the yield of electrons. The thiosulfate oxidation rate of cell-free extracts of strain GBsoxFDelta was increased when supplemented with SoxF isolated from the wild type. However, SoxF did not affect the thiosulfate-oxidizing activity of the Sox enzyme system as reconstituted from the 'as-isolated' four Sox proteins. These data demonstrated that SoxF enhanced chemotrophic thiosulfate oxidation in vivo and acted on some component or condition present in whole cells and cell-free extracts but not present in the reconstituted system.
Bardischewsky
Frank
F
Lehrstuhl für Technische Mikrobiologie, Fachbereich Bio und Chemieingenieurwesen, Universität Dortmund, Dortmund, Germany.
Quentmeier
Armin
A
Friedrich
Cornelius G
CG
D001426:Bacterial Proteins / Q000502:physiology*; D005420:Flavoproteins / Q000502:physiology*; D010084:Oxidation-Reduction; D042084:Paracoccus pantotrophus / Q000378:metabolism*; D013885:Thiosulfates / Q000378:metabolism*
D001426:Bacterial Proteins; D005420:Flavoproteins; C107539:SoxF protein, Paracoccus; D013885:Thiosulfates