Figure 1.

Alignment of the amino acid sequences of seven full length Arabidopsis and Saccharomyces ZIP proteins (IRT1, ZIP1, ZIP2, ZIP3, ZIP4, ZRT1, and ZRT2). The eight transmembrane domains predicted for each these proteins are numbered I–VIII. Residues highlighted in blue are identical, and residues highlighted in green represent conservative substitutions. The histidines found in the variable region between transmembrane domains III and IV are highlighted in gold. Residues highlighted in pink are conserved histidines or acidic residues found within predicted transmembrane helices.