Regulatory Mechanism of Nicotine Degradation in Pseudomonas putida

摘要: Nicotine, a toxic and addictive alkaloid from tobacco, is an environmental pollutant in areas near cigarette production facilities. Over the last decade, our group has studied, depth, pyrrolidine pathway of nicotine degradation Pseudomonas putida S16. However, little known regarding whole mechanism(s) regulating transcription gene cluster. In present study, we comprehensively elucidate overall view NicR2-mediated two-step mechanism 3-succinoyl-pyridine (SP) biotransformation, which involves association free NicR2 with two promoters dissociation NicR2-promoter complex. can bind to another promoter, Pspm, regulate expression nicotine-degrading genes middle nic2 cluster, are not controlled by previously reported Phsp promoter. We identified function inverted repeat bases on responsible for binding found out that -35/-10 motif RNA polymerase overlapped site. clarify exact role 6-hydroxy-3-succinoyl-pyridine (HSP), acts as antagonist may prevent but cannot release promoters. Finally, regulatory model proposed, consists three parts: interaction between (Pspm Phsp), effectors (HSP SP), polymerase.IMPORTANCE report entire process underlying controls specific nucleotides Pspm promoter binding. HSP was further demonstrated antagonist, prevents promoters, locking derepression conformation. The competition essential initiate genes. This study extends understanding molecular mechanisms biodegradation pollutants toxicants.