5COT:
reference: Structure and two-metal mechanism of a eukaryal nick-sealing RNA ligase., Unciuleac MC, Goldgur Y, Shuman S, Proc Natl Acad Sci U S A. 2015 Nov 10;112(45):13868-73. doi:, 10.1073/pnas.1516536112. Epub 2015 Oct 28. PMID: 26512110

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).