Cloning of the netropsin resistance genes from Streptomyces flavopersicus NRRL 2820

Streptomyces flavopersicus NRRL 2820 (synonym: Streptomyces netropsis DSM40093) is resistant to the N-methylpyrrole-containing oligopeptide antibiotic netropsin. A 9.38 kb DNA-fragment was isolated from a genomic library of Streptomyces flavopersicus using an Escherichia coli-Streptomyces lividans shuttle vector which enables S. lividans to grow on netropsin-containing agar plates. By subcloning, the resistance was conferred to a 5.9 kb EcoRV fragment. DNA sequence analysis of this EcoRV fragment revealed two open reading frames (netP1, 1556 bp and netP2, 1773 bp). The deduced proteins share significant similarity to each other (27% identity) and to the large family to ABC-type multidrug resistance proteins. In each protein a conserved transmembrane and ATP binding domain was identified. Deletion analysis showed that both proteins are necessary for netropsin resistance indicating that the proteins form a heterodimeric ABC-transporter exporting netropsin.