Identification of two outer membrane proteins involved in the oxidation of sulphur compounds inThiobacillus ferrooxidans

Shift of three Thiobacillus ferrooxidans strains from Fe(II) to S0 or thiosulphate liquid medium caused distinctive changes in the outer membrane protein profile. In addition to a new 55-kDa protein which was synthesized only in the presence of sulphur compounds, a higher expression of a 47-kDa protein was observed. This latter protein appeared to be constitutively synthesized, since it was detectable in small amounts even in tile presence of ferrous iron as sole energy source, but its expression was greatly enhanced when elemental sulphur or thiosulphate were present in the growth medium.