INVESTIGADORES
CHALON Miriam Carolina
artículos
Título:
Redox-active tyrosine residue in the microcin J25 molecule
Autor/es:
MIRIAM C. CHALÓN; NATALIA WILKE; JENS PEDERSEN; STEFANO RUFINI; ROBERTO D. MORERO; LEONARDO CORTEZ; ROSANA N. CHEHÍN; RICARDO N. FARIAS; PAULA A. VINCENT
Revista:
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Año: 2011 vol. 406 p. 366 - 370
ISSN:
0006-291X
Resumen:
Microcin J25 (MccJ25) is a 21 amino acid lasso-peptide antibiotic produced by Escherichia coli and composed
of an 8-residues ring and a terminal tail passing through the ring. We have previously reported
two cellular targets for this antibiotic, bacterial RNA polymerase and the membrane respiratory chain,
and shown that Tyr9 is essential for the effect on the membrane respiratory chain which leads to superoxide
overproduction. In the present paper we investigated the redox behavior of MccJ25 and the mutant
MccJ25 (Y9F). Cyclic voltammetry measurements showed irreversible oxidation of both Tyr9 and Tyr20 in
MccJ25, but infrared spectroscopy studies demonstrated that only Tyr9 could be deprotonated upon
chemical oxidation in solution. Formation of a long-lived tyrosyl radical in the native MccJ25 oxidized
by H2O2 was demonstrated by Electron Paramagnetic Resonance Spectroscopy; this radical was not
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.
of an 8-residues ring and a terminal tail passing through the ring. We have previously reported
two cellular targets for this antibiotic, bacterial RNA polymerase and the membrane respiratory chain,
and shown that Tyr9 is essential for the effect on the membrane respiratory chain which leads to superoxide
overproduction. In the present paper we investigated the redox behavior of MccJ25 and the mutant
MccJ25 (Y9F). Cyclic voltammetry measurements showed irreversible oxidation of both Tyr9 and Tyr20 in
MccJ25, but infrared spectroscopy studies demonstrated that only Tyr9 could be deprotonated upon
chemical oxidation in solution. Formation of a long-lived tyrosyl radical in the native MccJ25 oxidized
by H2O2 was demonstrated by Electron Paramagnetic Resonance Spectroscopy; this radical was not
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.
Escherichia coli and composed
of an 8-residues ring and a terminal tail passing through the ring. We have previously reported
two cellular targets for this antibiotic, bacterial RNA polymerase and the membrane respiratory chain,
and shown that Tyr9 is essential for the effect on the membrane respiratory chain which leads to superoxide
overproduction. In the present paper we investigated the redox behavior of MccJ25 and the mutant
MccJ25 (Y9F). Cyclic voltammetry measurements showed irreversible oxidation of both Tyr9 and Tyr20 in
MccJ25, but infrared spectroscopy studies demonstrated that only Tyr9 could be deprotonated upon
chemical oxidation in solution. Formation of a long-lived tyrosyl radical in the native MccJ25 oxidized
by H2O2 was demonstrated by Electron Paramagnetic Resonance Spectroscopy; this radical was not
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.
2O2 was demonstrated by Electron Paramagnetic Resonance Spectroscopy; this radical was not
detected when the reaction was carried out with the MccJ25 (Y9F) mutant. These results show that
the essential Tyr9, but not Tyr20, can be easily oxidized and form a tyrosyl radical.