ABSTRACT
A lower accumulation of toxic metals in consumable tissues would be desirable for reducing dietary intake. Conversely, the specific engineering of high-level uptake of metals in noncrop plants might prove useful for phytoremediation of metal-contaminated soil and water systems. Amino acid sequence identity among ABC-type proteins is primarily restricted to the region surrounding the NBS; the hydrophobic domains containing the transmembrane helices display little or no similarity with each other. The different domains may be encoded by different genes, as for some of the bacterial transport systems, or by a single gene, as for all eukaryotic members of the family. The plasmid containing this gene fusion complemented LK100, suggesting that the fusion protein functions correctly and is likely to be in its proper intracellular location. Cells harboring this gene fusion were fractionated as before, and the various fractions were examined by immunoblot analysis using monoclonal antibodies directed against beta-galactosidase.
