Fig. 2: Molecular dynamics simulation of interior hydration.

Representative snapshots of solvent molecules consistently identified in MD simulation runs. a The left panel shows the newly identified water chain between the b-type hemes in top view orientation. b The right panel shows the path of water molecules entering at the CydAB interface and running towards the oxygen reduction site. Residues lining the putative proton channel are indicated. CydA, gray; CydB, light grey; b-type hemes purple; heme d, coral. Water molecules are shown as tri-sphere units (O: red; H: white).