FIG 2.

(A) Characterization of the light- and oxygen-dependent activities of the M. marinus BldP1 and A. vinosum BldP2 proteins. (A) The effects of oxygen and blue light on the motility of the MG1655 yhjH strain expressing the BldP1 and BldP2 proteins were assayed in semisolid agar at various oxygen levels in the absence or presence of blue light. Plates were incubated at 30°C for 12 h in air (21% O₂) under micro-oxic (6 to 16% O₂) or anoxic (0% O₂) conditions. Dark, no light; Light, blue light irradiation (5 s of light and 60 s of dark); V, pMAL-c5x (empty vector); BldP1, pMal_BldP1; BldP2, MAL-BldP2. (B) Absorbance spectra of the purified MBP-PAS9-GGDEF protein fragment from A. vinosum BldP. The black trace shows the spectrum of the protein purified from E. coli, and the gray trace shows the spectrum after reconstitution with excess hemin in vitro. The inset shows an enlarged part of the spectrum emphasizing the Soret band (∼420 nm) indicative of the trace amounts of heme found in the “as-purified” protein.