FIG. 1.

Twist angles calculated from atomic positions and central lines of β-strand in protein 1ATZ (PDB ID) sheet A. (A) The atomic structure of β-strands shown as ribbons is superimposed with the splines (dots) of the β-strands that are sampled with a 1.1 Å vector length. The pairing segment (marked with dashed lines) and vectors are marked (black arrows). (B) Twist angles measured using the discrete method. (C) Twist angles measured from splines. Those angles measured using nearest-vector and sequential-vector methods are marked with circles and triangles, respectively. Pair (1,2) is colored dark in (B, C). PDB, Protein Data Bank.