NOXA-B (cyan) with amino acids (black) signifying 'hot-spot' residues. The canonical parent CC-Di (gray) is used to generate sequences that assemble into parallel homomeric coiled coils (orange, with hot-spot residues in black) and a parallel heterodimeric coiled coil (acidic partner in red, basic partner in blue and hot-spot residues in black) that bind to MCL-1.