Characterization of a putative chromosome segregation and condensation protein (ScpB) in an acidophilic iron‒oxidizing bacterium Acidithiobacillus ferrooxidans

　Acidithiobacillus ferrooxidans is one of the most widely used microorganisms in bioleaching operations to recover copper from low-grade copper sulfide. This bacterium uses ferrous iron and reduced inorganic sulfur compounds (RISCs) as energy sources. Transcriptions of genes thought to be involved in the oxidation of RISCs have been known to be highly activated in A. ferrooxidans cells grown on RISCs, while transcriptions of genes involved in the iron oxidation were repressed in the cells grown on RISCs. A gene encoding a putative chromosome segregation and condensation protein (ScpB) with a helix-turn-helix motif was found in the upstream region of sulfide : quinone oxidoreductase gene, whose expression was up-regulated in cells grown in sulfur and tetrathionate. A semi-quantitative PCR analysis using cDNA prepared from iron-, sulfur-, or tetrathionate-grown cells revealed that the transcription of scpB was up-regulated in cells grown on sulfur or tetrathionate as the energy source. Electrophoretic mobility shift assays were employed to examine whether the ScpB functions as a transcription factor. The result indicated that the recombinant His-tagged ScpB protein was able to nonspecifically bind in vitro to DNA. This is the first report on a direct association of ScpB with DNA.

原著論文 (Original paper)