1AOS:
reference: Human argininosuccinate lyase: a structural basis for intragenic complementation., Turner MA, Simpson A, McInnes RR, Howell PL, Proc Natl Acad Sci U S A 1997 Aug 19;94(17):9063-8. PMID: 9256435

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