Homology model of the multidrug transporter LmrA from Lactococcus lactis.

LmrA is an ATP dependent multidrug transporter from Lactococcus lactis conferring antibiotic resistance to 17 out of 21 most frequently administered antibiotics. Starting from the dimeric crystal structure of Vc-MsbA, we built two homology models, with NBD:NBD interfaces reflecting the nonenergized and energized state, respectively. The TMD:TMD topology of the dimer is consistent with the previously obtained substrate photoaffinity labeling pattern suggesting binding of substrates at the TMD:TMD interface involving helix 3 of one monomer and helices 5 and 6 of the other monomer.