FIG. 4.

Expression of a soluble, acid-stable cytochrome in strain JCM 7811 anaerobically cultured with H₂ as the electron donor and Fe³⁺ as the electron acceptor. (A) CBB-stained SDS-polyacrylamide gel. Lanes 1 and 2 were loaded with the respective supernatants from crude extracts of cells grown with Fe²⁺/O₂ and H₂/Fe³⁺; lane 3 shows the cytochrome purified from the anaerobic extract loaded into lane 2. (B) Absorbance spectra of the oxidized (Ox; dashed line) and reduced (Red; solid line) forms of the cytochrome. The inset shows the difference spectrum representing the absolute spectrum of the cytochrome obtained by subtracting the spectrum of the oxidized form from that of the reduced form.