Fig. 3

Nucleotide binding to the complex I. a The structure of the NADH-binding pocket of NuoEF in the reduced state of the protein with bound NADH in the tight position, b that of NuoEF in the reduced state of the protein with bound NAD⁺ close to the tight position and (c) that of NuoEF in the oxidized state of the protein with bound NAD⁺ in the loose position