Fig. 5.

Displacements during successive phases. A serves to identify the main secondary elements: In this orientation (same as in Fig. 1A), the axes of event Q1 (αG helices, in blue) and the axes of event Q2 (αH helices, in brown) can be recognized. The βG helices are shown in yellow, βH in red. The βCD loops are shown in purple, βE and βF in orange, and βNA, βA, and βEF in gray. B–F use the same orientation (but subunits are colored as in Fig. 1). The backbone thickness is drawn proportional to the amplitude of motion during each transition phase: (B) first tertiary phase. (C) Event Q1. D) second tertiary phase. (E) Event Q2. (F) third tertiary phase.