Analysis of long-range contacts. (A and B) Contact maps of 23S rRNA and FhuA, whose P(s) values are provided in Fig. 1. In FhuA, the long-range contacts (s ≳ 100), enclosed by a yellow box, are formed between the structure made of N-terminal sequences (i = 1–150) and surrounding β-strands forming the barrel. In 23S-rRNA, the locations of the clusters of long-range contacts formed at the interfaces between contact domains are highlighted using different colors on each range of sequences along with the 3D structures. (C) Histogram of the density of long-range contacts calculated for RNA and protein structures in the PDB. To see this figure in color, go online.