Emr, an Escherichia coli locus for multidrug resistance.
AUTOR(ES)
Lomovskaya, O
RESUMO
An Escherichia coli chromosomal DNA fragment cloned on a multicopy plasmid conferred resistance to carbonylcyanide m-chlorophenylhydrazone, nalidixic acid, and a number of other toxic compounds. The sequence of the cloned emr locus located at minute 57.5 of the chromosome revealed two open reading frames, emrA and emrB. emrB encodes a highly hydrophobic 56.2-kDa peptide, with 14 potential alpha-helices to span the inner membrane. The peptide is homologous to QacA, a multidrug-resistant pump from Staphylococcus aureus, and belongs to a gene family that includes tetracycline-resistant pumps of Gram-positive bacteria and the galactose/H+ symporter of E. coli. emrA encodes a putative 42.7-kDa peptide containing a single hydrophobic domain and a large C-terminal hydrophilic domain. An active pho-fusion to the C domain suggested that EmrA is a membrane protein. Disruption of emrB significantly increased sensitivity of cells to uncouplers. The cellular content of uncoupler increased in the order: overexpressed emrB cells greater than wild type greater than emrB-.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=50039Documentos Relacionados
- Differential regulation of the mcb and emr operons of Escherichia coli: role of mcb in multidrug resistance.
- EmrR is a negative regulator of the Escherichia coli multidrug resistance pump EmrAB.
- Structure of the multidrug resistance efflux transporter EmrE from Escherichia coli
- The EmrR Protein Represses the Escherichia coli emrRAB Multidrug Resistance Operon by Directly Binding to Its Promoter Region
- Thiolactomycin resistance in Escherichia coli is associated with the multidrug resistance efflux pump encoded by emrAB.