R. Edgar et E. Bibi, MDFA, AN ESCHERICHIA-COLI MULTIDRUG-RESISTANCE PROTEIN WITH AN EXTRAORDINARILY BROAD-SPECTRUM OF DRUG RECOGNITION, Journal of bacteriology, 179(7), 1997, pp. 2274-2280
Multidrug resistance (MDR) translocators recently identified in bacter
ia constitute an excellent model system for studying the MDR phenomeno
n and its clinical relevance, Here we describe the identification and
characterization of an unusual MDR gene (mdfA) from Escherichia coli,
mdfA encodes a putative membrane protein (MdfA) of 410 amino acid resi
dues which belongs to the major facilitator superfamily of transport p
roteins, Cells expressing MdfA from a multicopy plasmid are substantia
lly more resistant to a diverse group of cationic or zwitterionic lipo
philic compounds such as ethidium bromide, tetraphenylphosphonium, rho
damine, daunomycin, benzalkonium, rifampin, tetracycline, and puromyci
n. Surprisingly, however, MdfA also confers resistance to chemically u
nrelated, clinically important antibiotics such as chloramphenicol, er
ythromycin, and certain aminoglycosides and fluoroquinolones. Transpor
t experiments with an E. coli strain lacking F-1-F-0 proton ATPase act
ivity indicate that MdfA is a multidrug transporter that is driven by
the proton electrochemical gradient.