Comparison of the VvZIP3 amino acid sequence with its homologues from other plant species. Alignment was performed with highest similar homologous sequences. Identical residues are blackened. The eight transmembrane domains are highlighted by black lines under the sequences and numbered from I to VIII, as predicted by TMHMM and TMpred (see methods). HMD, highlighted by light gray line, depicts the histidine-rich metal-binding domain. A potential metal binding motif highly conserved (HxGHVH) is marked between TM-III and TM-IV with asterisks under the sequences. The N-terminus line under the VvZIP3 sequence (grey box) highlights a possible signal peptide for plasma membrane localization obtained by WOLF-PSORT-II software (see methods).