Escherichia coli Molybdoenzymes Can Be Activated by Protein FA from Several Gram-negative Bacteria

Summary: Six Gram-negative bacteria (Klebsiella pneumoniae, Erwinia chrysanthemi, Proteus vulgaris, Serratia marescens, Salmonella typhimurium, and Pseudomonas aeruginosa) were shown to contain an FA-type protein capable of activating aponitrate reductase, apotrimethylamine N-oxide reductase and apoformate dehydrogenase of Escherichia coli. Protein FA activity was highest in Erwinia chrysanthemi and lowest in Pseudomonas aeruginosa. All the species also contained the low-M r (≤ 1500) heat-resistant material previously reported to be necessary for the protein-FA-dependent activation of E. coli chlB nitrate reductase.