Disulfide linkage in the coiled-coil domain of subunit H of A1AO ATP synthase from Methanocaldococcus jannaschii and the NMR structure of the C-terminal segment H85–104

The C-terminal residues 98–104 are important for structure stability of subunit H of A1AO ATP synthases as well as its interaction with subunit A. Here we determined the structure of the segment H85–104 of H from Methanocaldococcus jannaschii, showing a helix between residues Lys90 to Glu100 and flexible tails at both ends. The helix–helix arrangement in the C-terminus was investigated by exchange of hydrophobic residues to single cysteine in mutants of the entire subunit H (HI93C, HL96C and HL98C). Together with the surface charge distribution of H85–104, these results shine light into the A–H assembly of this enzyme.