title: Mutations affecting DNA-binding activity of the MexR repressor of mexR-mexA-mexB-oprM operon expression.
abstract: We have isolated 25 MexR mutants that retained their dimerizing ability but were unable to bind mexOP DNA. Surprisingly, 20 mutations were located in the hydrophobic core region at alpha4, W1, alpha2, alpha3, and beta2, and only 3 were in positively charged residues. These results verified that DNA binding is mediated by distinct regions of MexR and showed the importance of the hydrophobic core region of the DNA-binding domain.
authors.affiliation: Department of Molecular Life Science, Tokai University School of Medicine, Isehara 259-1193, Japan.
authors.forename: Kohjiro
authors.initials: K
authors.lastname: Saito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Akama
authors.forename: Eisaku
authors.initials: E
authors.lastname: Yoshihara
authors.forename: Taiji
authors.initials: T
authors.lastname: Nakae
mesh_terms: D001398:Aztreonam / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism*; D018432:Drug Resistance, Multiple; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D009154:Mutation; D015242:Ofloxacin / Q000494:pharmacology; D009876:Operon; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; C118598:MexA protein, Pseudomonas aeruginosa; C118597:MexB protein, Pseudomonas aeruginosa; C423620:MexR protein, Pseudomonas aeruginosa; C402263:OprM protein, Pseudomonas aeruginosa; D012097:Repressor Proteins; D015242:Ofloxacin; D001398:Aztreonam