Figure 1.

The OCP Structure and Position of the Mutated Amino Acids Arg155 and Glu244.

(A) N-terminal domain is in blue, and the C-terminal domain is in red. The carotenoid is shown as orange sticks, and Arg155 (N-terminal domain) and Glu244 (C-terminal domain) are shown as sticks colored green for sidechains, red for oxygen atoms, and blue for nitrogen atoms.

(B) Surface view with similar orientation and coloring as in (A).

(C) Close-up of the central interdomain interface and the salt bridge between Arg155 and Glu244. Also shown are structurally conserved water molecules (yellow spheres).

(D) Close-up of the central interdomain interface with Lys substituted for Arg155. The Lys rotamer with the closest approach to Glu 244 was used in the model.