Disulfide linkage in the coiled-coil domain of subunit H of A₁A_O ATP synthase from Methanocaldococcus jannaschii and the NMR structure of the C-terminal segment H_85–104

Abstract 

The C-terminal residues 98–104 are important for structure stability of subunit H of A₁A_O ATP synthases as well as its interaction with subunit A. Here we determined the structure of the segment H_85–104 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 (H_I93C, H_L96C and H_L98C). Together with the surface charge distribution of H_85–104, these results shine light into the A–H assembly of this enzyme.

Abbreviations: DTT, dithiothreitol, EDTA, ethylenediaminetetraacetic acid, IPTG, isopropyl-β-d-thio-galactoside, NMR, nuclear magnetic resonance, NOE, nuclear Overhauser effect, NOESY, NOE spectroscopy, NTA, nitrilotriacetic acid, PAGE, polyacrylamide gel electrophoresis, PCR, polymerase chain reaction, RMSD, root mean square distance, SDS, sodium dodecyl sulfate, Tris, tris-(hydroxymethyl) aminomethane

Keywords: Archaea, A₁A_O ATP synthase, ATP synthase, Methanogen, Subunit H, Methanocaldococcus jannaschii