INVESTIGADORES
BELLOMIO Augusto
artículos
Título:
TYROSINE 9 IS THE KEY AMINOACID IN MICROCIN J25 SUPEROXIDE OVERPRODUCTION
Autor/es:
CHALÓN MC; BELLOMIO A; SOLBIATI J; MORERO RD; FARIAS RN; VINCENT PA
Revista:
FEMS MICROBIOLOGY LETTERS
Editorial:
Blackwell Pub
Referencias:
Lugar: Oxford ; Año: 2009 vol. 300 p. 90 - 96
ISSN:
0378-1097
Resumen:
Escherichia coli microcin J25 (MccJ25) is a lasso-peptide antibiotic comprising 21 L-amino acid residues (G1-G-A-G-H5-V-P-E-Y-F10-V-G-I-G-T15-P-I-S-F-Y20-G). MccJ25 has two independent substrates: RNA-polymerase and the membrane respiratory chain. The latter is mediated by oxygen consumption inhibition together with an increase of superoxide production. In the present paper, the antibiotic MccJ25 was engineered by substituting Tyr9 or Tyr20 with phenylalanine. Both mutants were well transported into the cells and remained active on RNA-polymerase. Only the Y9F mutant lost the ability to overproduce superoxide and inhibit oxygen consumption. The last results confirm that the Tyr9, and not Tyr20, is involved in the MccJ25 action on the respiratory chain target.