Characterization of the superoxide dismutase gene and its upstream region from Methanobacterium thermoautotrophicum Marburg.

A gene (sod) encoding superoxide dismutase (SOD) was isolated from the strictly anaerobic archaeon Methanobacterium thermoautotrophicum Marburg. Its identify was confirmed by functional complementation of an Escherichia coli mutant strain lacking SOD activity and by DNA sequence analysis of a cloned fragment. Upstream of sod, separated by a 5-bp intergenic region, lies the open reading frame orfk which potentially codes for a protein of 209 amino acid residues. The amino acid sequence for this presumptive product had a similarity coefficient of 55.5% to a subunit of the alkyl hydroperoxide reductase (encoded by the ahpC gene) from Salmonella typhimurium.