Figure 5
Thioredoxin-binding patch defined by the covalent EcNTR–Trx complex. (a) The EcNTR dimer in the FO conformation (PDB code 1tde
). One subunit is shown in green and the solvent-accessible surface of the other is shown in orange. Residues Gly129 and Arg130 in the NADPH domain form the only hydrogen bonds to the FAD domain in the FO conformation. These residues (yellow) together with Ala237 provide all five of the hydrogen bonds formed upon Trx binding to the FR conformation. The residues interacting in the dimer interface are adjacent to the two loops (blue) that possibly provide some selectivity towards Trx isoforms. The association of Trx with this area prior to the conformational shift would break the inter-domain hydrogen bonds and thereby facilitate the shift. (b) A close-up view with hydrogen bonds indicated as dotted lines. (c) Solvent-accessible surface of the same area. |