The SMR family: a novel family of multidrug efflux proteins involved with the efflux of lipophilic drugs.
The sequenced members of a novel family of small, hydrophobic, bacterial multidrug-resistance efflux proteins, which we have designated the small multidrug resistance (SMR) protein family, are identified and analysed. Two distinct clusters of proteins were identified within this family: (i) small multidrug efflux systems; and (ii) Sug proteins, potentially involved in the suppression of groEL mutations. Hydropathy and residue distribution analyses of this family suggest a structural model in which the polypeptide chain spans the membrane four times as mildly amphipathic alpha-helices. The roles of specific residues, a possible mechanistic model of drug efflux, and the primary physiological role(s) of the SMR proteins are discussed.
Paulsen
I T
IT
School of Biological Sciences, University of Sydney, Australia.
Skurray
R A
RA
Tam
R
R
Saier
M H
MH
Turner
R J
RJ
Weiner
J H
JH
Goldberg
E B
EB
Grinius
L L
LL
D000595:Amino Acid Sequence; D017920:Antiporters; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D018432:Drug Resistance, Multiple; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D010802:Phylogeny; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid
D017920:Antiporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D010455:Peptides; C075436:EmrE protein, E coli