Figure 10.

Alignment of predicted transmembrane segments in P3A H⁺-ATPases. Asterisks mark residues of potential importance for proton coordination and pumping based on evidence from mutagenesis and analysis of a crystal structure for AtAHA2 (Pedersen et al., 2007). The number of the amino acid residue in AtAHA2 is indicated above each asterisk. R655 in M5, which seems important for controlling backflow of H⁺ at high electrochemical gradients (Pedersen et al., 2007), is lacking in some chlorophyte H⁺-ATPases.