title: Origin of tetracycline efflux proteins: conclusions from nucleotide sequence analysis.
abstract: The sequences of six tetracycline efflux proteins and three transport proteins which have some resemblance to them were compared. The tetracycline efflux proteins fall into three families: (i) those encoded by pBR322, RP1, and Tn10 (Escherichia coli); (ii) pT181 (Staphylococcus aureus) and pTHT15 (Bacillus subtilis); and (iii) tet347 (Streptomyces rimosus). There is global sequence homology within each of the first two families, but there is none between the families. The pT181/pTHT15 family shares close homology with the N-terminal half of the methylenomycin A efflux protein (Streptomyces coelicor), while tet347 resembles the C-terminal half. Portions of the N-terminal half of the Tn10-encoded protein show significant resemblance to portions in the N-terminal half of the pT181/pTHT15 family, but this sometimes occurs among transport proteins which do not have a common substrate. Tetracycline efflux proteins, therefore, appear to have arisen on at least two, or possibly three, separate occasions, probably from other transport proteins.
authors.affiliation: Department of Biomedical Research Computing, Lederle Laboratories, American Cyanamid, Pearl River, New York 10965.
authors.forename: R P
authors.initials: RP
authors.lastname: Sheridan
authors.forename: I
authors.initials: I
authors.lastname: Chopra
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D005075:Biological Evolution; D002352:Carrier Proteins / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid; D013211:Staphylococcus aureus / Q000235:genetics; D013302:Streptomyces / Q000235:genetics; D013752:Tetracycline / Q000378:metabolism*; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D013752:Tetracycline