2I4L:
reference: Structures of Two Bacterial Prolyl-tRNA Synthetases with and without a cis-Editing Domain., Crepin T, Yaremchuk A, Tukalo M, Cusack S, Structure. 2006 Oct;14(10):1511-25. PMID: 17027500

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