FIG. 4.

Tetrameric arrangement of WrbA and binding of NADH. (A) Cartoon representation of the tetramer. A single monomer is shown, colored as described in the legend of Fig. 1. Note the extended loop 2 region (Fig. 2) interacting with a neighboring monomer. (B) Surface representation of the tetramer, centered on the active site of one monomer. The picture shows a PEG molecule bound at the active site, an NADH molecule in close proximity, and several further PEG molecules along a dimer interface. (C) Stereo representation of a close-up of the active site in the same orientation as in panel B. The left and right images are for the left and right eyes, respectively. The nicotinamide ring of NADH stacks onto the side chain of Tyr 12.