Decomposition of backbone dynamics.

<p>(A) Probability of hinge bending and twisting motions. Motions coordinated by a single flexible hinge are referred to as type Bend 1 (B) and Twist 1 (T), respectively. Bending and/or twisting around a pair of hinges is characterized by four combinations of bending (B) and twisting (T) (motion types BB, BT, TB, TT). Motions coordinated by more than 2 hinges are grouped in category M. (B) Number of hinge residues utilized for single-hinge motions. (C, D) Probability by which a residue is identified as a hinge site in the single-hinge (C) and double-hinge (D) bending and twisting motions. (E-F) Examples for bending (E) and twisting (F) around a single hinge. (G-H) Examples of correlated bending (G) and mixed bending/twisting (H) around a pair of hinges. Helical segments moving as rigid domains are coloured in blue and red, the hinge residues are highlighted in green. Screw axes are shown in grey. A larger projection of the screw axis with respect to the helix axis indicates a higher percentage of twisting. Spheres label the Cα atoms of G33 in TM-N and L49 in TM-C.