1PBR:
reference: Structure of the A site of Escherichia coli 16S ribosomal RNA complexed with an aminoglycoside antibiotic., Fourmy D, Recht MI, Blanchard SC, Puglisi JD, Science 1996 Nov 22;274(5291):1367-71. PMID: 8910275

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