Reduction of U(VI) by the deep subsurface bacterium, Thermus scotoductus SA-01, and the involvement of the ABC transporter protein

• Published in: Chemosphere (Oxford) Vol. 86; no. 6; pp. 572 - 577
• Main Authors: Cason, Errol Duncan, Piater, Lizelle Ann, Heerden, Esta van
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2012; Elsevier
• Subjects: ABC transporter protein; Applied sciences; ATP-Binding Cassette Transporters - chemistry; ATP-Binding Cassette Transporters - genetics; ATP-Binding Cassette Transporters - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biodegradation of pollutants; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Electron Transport; Engineering and environment geology. Geothermics; Environment and pollution; Environmental Pollutants - isolation & purification; Environmental Pollutants - metabolism; Environmental Pollutants - toxicity; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Metal resistance; Models, Molecular; Mutation; Oxidoreductases - isolation & purification; Oxidoreductases - metabolism; Pollution; Pollution, environment geology; Protein Conformation; Soil and sediments pollution; Thermophile; Thermus - cytology; Thermus - drug effects; Thermus - enzymology; Thermus - metabolism; Thermus scotoductus SA-01; Uranium - isolation & purification; Uranium - metabolism; Uranium - toxicity; Uranium(VI) reduction; Thermus scotoductus SA-01; Thermophile; Uranium(VI) reduction; Metal resistance; ABC transporter protein; Radioactive pollution; Enzyme; Biostimulation; Thermophily; Radioisotope; Heavy metal; Chemical reduction; Actinide; Trace element; Uranium; Decontamination; Biotransformation; Bacteria; Oxidoreductases; Bioremediation; Carrier protein; Reductase
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2011.10.006

► We grew Thermusscotoductus SA-01 aerobically in up to 1.25 mM uranium. ► Using whole cells SA-01 reduced low levels of U(VI) in under 20 h with various electron donors. ► TEM analysis showed extracellular and membrane-bound accumulation of uranium. ► A peptide ABC transporter, peptide-binding protein is shown to be capable of U(VI) interactions. ► A possible mechanism for uranium(VI) reduction by the protein is elucidated. In this study we investigated the effect of uranium on the growth of the bacterium Thermus scotoductus strain SA-01 as well as the whole cell U(VI) reduction capabilities of the organism. Also, site-directed mutagenesis confirmed the identity of a protein capable of a possible alternative mechanism of U(VI) reduction. SA-01 can grow aerobically in up to 1.25 mM uranium and has the capability to reduce low levels of U(VI) in under 20 h. TEM analysis performed on cells exposed to uranium showed extracellular and membrane-bound accumulation of uranium. The reductase-like protein was surprisingly identified as a peptide ABC transporter, peptide-binding protein. This study showcases the concept of protein promiscuity, where this protein with a distinct function in situ can also have the unintended function of a reactant for the reduction of U(VI).