AMPLIFICATION OF A NOVEL GENE, SANA, ABOLISHES A VANCOMYCIN-SENSITIVEDEFECT IN ESCHERICHIA-COLI

We have isolated an Escherichia coli gene which, when overexpressed, i s able to complement the permeability defects of a vancomycin-suscepti ble mutant. This gene, designated sanA, is located at min 47 of the E. coil chromosome and codes for a 20-kDa protein with a highly hydropho bic amino-terminal segment. A strain carrying a null mutation of the s anA gene, transferred to the E. coli chromosome by homologous recombin ation, is perfectly viable, but after two generations at high temperat ure (43 degrees C), the barrier function of its envelope towards vanco mycin is defective.