Fig. 3.

Ternary complex crystal structure of T. maritima chemotaxis proteins. (A) Close-ups of the pseudosymmetric interactions made by the opposite ends of CheW (green ribbons) and P5 (blue ribbons), and the interaction between the receptor tip (magenta ribbons) and CheW. Inset shows a schematic of dimeric CheA:CheW, with the crystallized unit boxed. (B) Ring structure formed by the ternary complex crystals. Three CheW domains and three P5 domains generate a ring, and each CheW binds one receptor tip (pink) between subdomains 1 and 2 (Left). Similar interactions between P5 with the distal end of receptors (purple) link rings “head-to-head” in the unit cell (Right). The P4 domains (gray), of which only the core elements are visible, project above and below the double-ring structure at the junction to P5.