Biochemical and spectroscopic characterization of the bacterial phytochrome of Pseudomonas aeruginosa

摘要: Phytochromes are photochromic biliproteins found in plants as well some cyanotrophic, photoautotrophic and heterotrophic bacteria. In many bacteria, their function is largely unknown. Here we describe the biochemical spectroscopic characterization of recombinant bacterial phytochrome from opportunistic pathogen Pseudomonas aeruginosa (PaBphP). The protein displays all characteristic features a bonafide phytochrome. contrast with cyanobacteria plants, chromophore this biliverdin IXalpha, which produced by heme oxygenase BphO P. aeruginosa. This was shown to be covalently attached via its A-ring endo-vinyl group cysteine residue outside defined bilin lyase domain plant cyanobacterial phytochromes. Site-directed mutagenesis identified Cys12 His247 being important for binding photoreversibility, respectively. PaBphP synthesized dark red-light-absorbing Pr form immediately converted into far-red-light-absorbing Pfr-enriched form. It shows red/far-red-light-induced photoreversibility A analog that lacks C15/16 double bond used show due 15Z/15E isomerization chromophore. Autophosphorylation demonstrated, confirming role sensor kinase two-component signaling system.