Purification and characterization of the antimicrobial peptide microcin N.
Microcins are low-molecular-weight proteins secreted by certain bacteria that act by limiting the growth of other bacteria that share the same ecological niche. In the present work, the previous microcin 24 system was resequenced.We detected three nucleotide differences in the microcin-coding gene that partially change the amino acid sequence. According to the present microcin nomenclature, we renamed the five genes constituting this microcin system (mcnRINAB), which are arranged in an operon-like structure: mcnR codes for a putative histone-like nucleoid protein regulator; mcnI codes for the immunity protein; mcnN encodes microcin N; and mcnA and mcnB correspond to an ATP-binding cassette transporter system. Purified microcin N has a molecular weight of 7274.23 Da, as determined by MS. This peptide was stable up to 100°C, resistant to treatment with lipase, lysozyme, trypsin, and chymotrypsin, and susceptible to degradation by proteinase K.
Centro de Investigacion Biomedica, Universidad Diego Portales, Santiago, Chile. gino.corsini@udp.cl
Gino
G
Corsini
Eduardo
E
Karahanian
Mario
M
Tello
Katia
K
Fernandez
Daniel
D
Rivero
Jose Miguel
JM
Saavedra
Alonso
A
Ferrer
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D004269:DNA, Bacterial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D015870:Gene Expression; D005798:Genes, Bacterial; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D004269:DNA, Bacterial; C020411:microcin