The SNQ2 gene of Saccharomyces cerevisiae, which encodes an ATP binding cassette protein responsible for resistance to the mutagen 4-nitroquinoline oxide, is regulated by the DNA-binding proteins PDR1 and PDR3. In a plasma membrane-enriched fraction from a pdr1 mutant, the SNQ2 protein is found in the 160-kDa over-expressed band, together with PDR5. The SNQ2 protein was solubilized with n-dodecyl beta-D-maltoside from the plasma membranes of a PDR5-deleted strain and separated from the PMA1 H(+/-)ATPase by sucrose gradient centrifugation. The enzyme shows a nucleoside triphosphatase activity that differs biochemically from that of PDR5 (Decottignies, A., Kolaczkowski, M., Balzi, E., and Goffeau, A. (1994) J. Biol. Chem. 269, 12797-12803) and is sensitive to vanadate, erythrosine B, and Triton X-100 but not to oligomycin, which inhibits the PDR5 activity only. Disruption of both PDR5 and SNQ2 in a pdr1 mutant decreases the cell growth rate and reveals the presence of at least two other ATP binding cassette proteins in the 160-kDa overexpressed band that have been identified by amino-terminal microsequencing.

• PMID: 7629127
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• PubMed

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Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, P.H.S.

Authors

Decottignies A, Lambert L, Catty P, Degand H, Epping EA, Moye-Rowley WS, Balzi E, Goffeau A

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