Solution structure of the cytoplasmic domain of NhaP2 a K/H antiporter from Vibrio cholera.

NhaP2 is a K/H antiporter from Vibrio cholerae which consists of a transmembrane domain and a cytoplasmic domain of approximately 200 amino acids, both of which are required for cholera infectivity. Here we present the solution structure for a 165 amino acid minimal cytoplasmic domain (P2MIN) form of the protein. The structure reveals a compact N-terminal domain which resembles a Regulator of Conductance of K channels (RCK) domain connected to a more open C-terminal domain via a flexible 20 amino acid linker.