The 2mFo − DFc electron density maps around (A) Lys 9, (B) Thr23, (C) Tyr50, (D) Tyr111, (E) Tyr190 and (F) Lys271, shown as a grey mesh and contoured at the root mean square electron density (1σ), using structure factors and atomic co-ordinates from the Protein Data Bank (PDB code: 1OKC). The carrier is shown in cartoon representation with side chains as sticks, coloured by domain (domain 1, blue; domain 2, yellow; domain 3, red), whereas the residues that are claimed to be modified are shown in green. Cardiolipins are shown in dark grey and carboxyatractyloside in teal. Water molecules are shown as red spheres. Hydrogen bonds are indicated by black dashed lines, with distances indicated (Å). The side-chain of Asn73, which interacts with Thr23, has been flipped to maximise its hydrogen-bonding potential.