Two enzymes catalyze the maturation of a lasso peptide in Escherichia coli.
Microcin J25 (MccJ25) is a gene-encoded lasso peptide secreted by Escherichia coli which exerts a potent antibacterial activity by blocking RNA polymerase. Here we demonstrate that McjB and McjC, encoded by genes in the MccJ25 gene cluster, catalyze the maturation of MccJ25. Requirement for both McjB and McjC was shown by gene inactivation and complementation assays. Furthermore, the conversion of the linear precursor McjA into mature MccJ25 was obtained in vitro in the presence of McjB and McjC, all proteins being produced by recombinant expression in E. coli. Analysis of the amino acid sequences revealed that McjB could possess proteolytic activity, whereas McjC would be the ATP/Mg(2+)-dependent enzyme responsible for the formation of the Gly1-Glu8 amide bond. Finally, we show that putative lasso peptides are widespread among Proteobacteria and Actinobacteria.
Duquesne
Sophie
S
Chimie et Biochimie des Substances Naturelles, UMR 5154 CNRS, Muséum National d'Histoire Naturelle, CP 54, 57 rue Cuvier, 75005 Paris, France.
Destoumieux-Garzón
Delphine
D
Zirah
Séverine
S
Goulard
Christophe
C
Peduzzi
Jean
J
Rebuffat
Sylvie
S
D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D006868:Hydrolysis; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D053719:Tandem Mass Spectrometry
D001430:Bacteriocins; D017931:DNA Primers; C020411:microcin