3K5Z:
reference: Structural basis for specific recognition of multiple mRNA targets by a PUF regulatory protein., Wang Y, Opperman L, Wickens M, Hall TM, Proc Natl Acad Sci U S A. 2009 Dec 1;106(48):20186-91. Epub 2009 Nov 9. PMID: 19901328

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