FIG. 1.

Spectral complex formation in the R. sphaeroides strain expressing the His₆-tagged H303A oxidase. The CBB3Δ strains carrying the corresponding plasmids were grown either aerobically by sparging with ambient air to an optical density at 600 nm of 0.4 to 0.5 (A) or anaerobically with DMSO in the dark for 5 days (B). The CBB3Δ strains containing pRK415 and pUI2803NHIS were used in these experiments as control strains. Seven hundred micrograms of the crude extracts were used to record the spectra between 400 and 950 nm. The peak or shoulder at 875 indicates the B875 complex (light harvesting complex I). The peaks at 800 and 850 represent the B800-B850 complex (light harvesting complex II).