Fig. 2
From: Origin and development of oligoadenylate synthetase immune system
Type I topoisomerase (TOPI) is highly conserved in lower Metazoa. a Domains of TOPI. Subdomain 1, subdomain 2, subdomain 3, the linker domain, and C-terminal domain are colored in green, red, purple, yellow and blue. Sequence identity to human TOPI and the size of this protein in the other five species are marked at the right-hand side. b Sequence alignment of TOPI proteins from distantly related species. Fragments containing five key residues are displayed and these key residues (colored in pink) show the strict amino acid identity