Fig 7. Influence of central G→A/T substitution in one chain or loop in one chain on the flexibility of the triple helix.

(A) Each point in the 4 plots is the projection of a vector from the center of the folded triple helix to the N-Terminus on the plane perpendicular to the vector pointing from the C-Terminus to the center of the triple helix. WT indicates the natively folded triple helix with an isotropic distribution indicating a fluctuation around the straight triple helix (standard deviation of the distribution indicated as black circle). The LOOP, ALA, THR label indicate simulations with a central loop segment of one chain (see also Fig 6A), a central G→A or G→T mutation in one strand, respectively. The LOOP case indicates a significant directional bending fluctuation. (B) illustration of the vectors and projection. (C) correlation of x/y-displacement for the wild type, the single G7aA and G7aT mutations and the triple helix with the looped out segment in one chain. Increased correlation indicates anisotropic bending fluctuations of one end of the triple helix relative to the other end.