Nickel-Resistance Determinants in Acidiphilium sp. PM Identified by Genome-Wide Functional Screening |
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| Authors: | Patxi San Martin-Uriz Salvador Mirete Pedro J. Alcolea Manuel J. Gomez Ricardo Amils Jose E. Gonzalez-Pastor |
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| Affiliation: | 1. Centro de Astrobiología (INTA-CSIC), Instituto Nacional de Técnica Aeroespacial, Torrejón de Ardoz, Madrid, Spain.; 2. Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas, Madrid, Spain.; 3. Centro de Biología Molecular Severo Ochoa (UAM-CSIC), Universidad Autónoma de Madrid, Madrid, Spain.; University of Cambridge, United Kingdom, |
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| Abstract: | Acidiphilium spp. are conspicuous dwellers of acidic, metal-rich environments. Indeed, they are among the most metal-resistant organisms; yet little is known about the mechanisms behind the metal tolerance in this genus. Acidiphilium sp. PM is an environmental isolate from Rio Tinto, an acidic, metal-laden river located in southwestern Spain. The characterization of its metal resistance revealed a remarkable ability to tolerate high Ni concentrations. Here we report the screening of a genomic library of Acidiphilium sp. PM to identify genes involved in Ni resistance. This approach revealed seven different genes conferring Ni resistance to E. coli, two of which form an operon encoding the ATP-dependent protease HslVU (ClpQY). This protease was found to enhance resistance to both Ni and Co in E. coli, a function not previously reported. Other Ni-resistance determinants include genes involved in lipopolysaccharide biosynthesis and the synthesis of branched amino acids. The diversity of molecular functions of the genes recovered in the screening suggests that Ni resistance in Acidiphilium sp. PM probably relies on different molecular mechanisms. |
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