Issues

Cover picture: Partial separation of degenerate site in asymmetrical ABC exporter. Ribbon diagram of nucleotide-binding domain dimer from crystal structure of TM287/288 (green/blue; Protein Data Bank accession no. 3QF4) with AMPPNP (yellow) bound at the degenerate site. Corresponding Walker A threonines (red) and D-loop residues TM288/N521 and TM287/S499 (violet) are in space fill. The empty active site is wide open, and the nucleotide-bound degenerate site retains some inter-NBD contact through opposing Walker A and D-loops. This figure was generated with PyMOL Molecular Graphics System (see research article by Csanády et al., 61–73).