Present address: Institut Pasteur. Unité de Biochimie Cellulaire, 25-28 rue du Docteur Roux, F-75015 Paris, France.
sbmC, a stationary-phase induced SOS Escherichia coli gene, whose product protects cells from the DNA replication inhibitor microcin B17
Article first published online: 8 MAR 2004
Volume 18, Issue 02, pages 301–311, October 1995
How to Cite
Baquero, M.R., Bouzon, M., Varea, J. and Moreno, F. (1995), sbmC, a stationary-phase induced SOS Escherichia coli gene, whose product protects cells from the DNA replication inhibitor microcin B17. Molecular Microbiology, 18: 301–311. doi: 10.1111/j.1365-2958.1995.mmi_18020301.x
- Issue published online: 8 MAR 2004
- Article first published online: 8 MAR 2004
- Received 11 April, 1995; revised 7 July, 1995; accepted 10 July, 1995.
- Cited By
Microcin B17 (MccB17) is a ribosomally synthesized peptide antibiotic of 43 amino acids that induces double-strand breaking of DNA in a DNA gyrase-dependent reaction. As a consequence, the SOS regulon is induced and massive DNA degradation occurs. In this work we have characterized an Escherichia coli gene, sbmC, that in high copy number determines high cell resistance to MccB17. sbmC encodes a cytoplasmic polypeptide of 157 amino acids (Mr, 18 095) that has been visualized in SDS—polyacrylamide gels. The gene is located at min 44 of the E. coli genetic map, close to the sbcB gene. sbmC expression is induced by DNA-damaging agents and, also, by the entry of cells into the stationary growth phase. A G → T transversion at the fifth nucleotide of the quasicanonical LexA-box preceding the gene makes recA cells 16-fold more resistant to exogenous MccB17. The gene product, SbmC, also blocks MccB17 export from producing cells. Altogether, our results suggest that SbmC recognizes and sequesters MccB17 in a reversible way.