(A) Close-up view of the GVGGP motif in context of a single subunit. An i,i+3 hydrogen bond characteristic of a right-handed β-turn is indicated, as is the sub-pocket occupied by the Val353 sidechain. Mesh shows a composite simulated annealing omit map (1σ). (B) Stereo view of the β-turn and its surrounding pocket, which is made up of two MHR loops (red), two helix 9/10 loops (orange), and the N-terminal ends of three junction helices (blue). The hexamer is rendered as a translucent surface. (C) The six β-turns (yellow sticks) in context of the hexamer. The surrounding MHR, 9/10 loops, and junction helices are colored as in (B).