Iron respiration-driven proton translocation in aerobic bacteria

Washed cell suspensions of Aquaspirillum magnetotacticum MS-1, A. itersonii E12639, Bacillus subtilis 6633, and Escherichia coli CSH27 translocated protons in response to the added oxidant O2 or NO3-, with triphenylmethylphosphonium bromide as the permeant ion. Iron respiration-driven proton translocation was observed in A. magnetotacticum MS-1, B. subtilis, and E. coli but not in a nonmagnetic strain of A. magnetotacticum (strain NM-1A) or with A. itersonii. Proton translocation to Fe3+ was totally inhibited by 500 microM NaN3 or 0.5 microM carbonyl cyanide m-chlorophenylhydrazone.