Fig. 3

Comparison of the apple MdCAX proteins with AtCAX proteins in Arabidopsis and ScVCX1 in yeast. Solid black lines and black box below the sequences indicate the 11 transmembrane regions (MR and M1 to M10) and the acidic helix region, respectively. Red lines and dots above the sequences indicate the two α-repeats and the two “GNxxE” motifs, respectively. Red and purple boxes indicate the N-terminal autoinhibitory region. Yellow dots below the sequences indicate the amino acid residues (Glu 83 of M1, Glu 230 and Asp 234 of the acidic helix) crucial for the coordination of calcium ions in ScVCX1. Purple and blue triangles indicate the residues crucial for the structural maintenance of ScVCX1 between M2 and M8, and between M3 and M7, respectively