1RIQ:
reference: Alanyl-tRNA synthetase crystal structure and design for acceptor-stem recognition., Swairjo MA, Otero FJ, Yang XL, Lovato MA, Skene RJ, McRee DE, de Pouplana LR, Schimmel P, Mol Cell 2004 Mar 26;13(6):829-41. PMID: 15053876

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