INVESTIGADORES
DELGADO Monica Alejandra
artículos
Título:
Mutations of Bacterial RNA Polymerase Leading to Resistance to Microcin J25*
Autor/es:
YUZENKOVA, JULIA; DELGADO, MONICA ALEJANDRA; NECHAEV, SERGEI; SAVALIA, DHRUTI; EPSHTEIN, VITALY; ARTSIMOVITCH, IRINA; MOONEY, RACHEL A.; LANDICK, ROBERT; FARIAS, RICARDO N.; SALOMON, RAUL; SEVERINOVA, KONSTANTIN; DELGADO, MONICA ALEJANDRA
Revista:
JOURNAL OF BIOLOGICAL CHEMISTRY
Editorial:
The American Society for Biochemistry and Molecular Biology (ASBMB)
Referencias:
Año: 2002 vol. 277 p. 50867 - 50875
ISSN:
0021-9258
Resumen:
A mutation in the conserved segment of the rpoC gene,
which codes for the largest RNA polymerase (RNAP)
subunit, b, was found to make Escherichia coli cells
resistant to microcin J25 (MccJ25), a bactericidal 21-
amino acid peptide active against Gram-negative bacteria
(Delgado, M. A., Rintoul, M. R., Farias, R. N., and
Salomon, R. A. (2001) J. Bacteriol. 183, 45434550). Here,
we report that mutant RNAP prepared from MccJ25-
resistant cells, but not the wild-type RNAP, is resistant
to MccJ25 in vitro, thus establishing that RNAP is a true
cellular target of MccJ25. We also report the isolation of
additional rpoC mutations that lead to MccJ25 resistance
in vivo and in vitro. The new mutations affect b
amino acids in evolutionarily conserved segments G, G,
and F and are exposed into the RNAP secondary channel,
a narrow opening that connects the enzyme surface
with the catalytic center. We also report that previously
known rpoB (RNAP b subunit) mutations that lead to
streptolydigin resistance cause resistance to MccJ25.
We hypothesize that MccJ25 inhibits transcription by
binding in RNAP secondary channel and blocking substrate
access to the catalytic center.