Figure 5.

NPA Binding by MDR-like Molecules.

(A) AtMDR1 expressed in yeast specifically binds NPA. Values are means of three independent experiments ±sd. Open circles, specific NPA binding to untransformed yeast strain; closed circles, specific NPA binding to yeast expressing AtMDR1; closed squares, NPA binding in the presence of a 1000-fold concentration of benzoic acid to yeast expressing AtMDR1.

(B) Arabidopsis membrane proteins identified by high-affinity NPA binding. Shown are Coomassie blue–stained, 10% SDS–polyacrylamide gels of high molecular mass proteins purified by gel filtration and NPA affinity chromatography. Proteins were first solubilized from microsomal (MS) or plasma membrane (PM) vesicles derived from seedlings.