2ADV:
reference: Insight into autoproteolytic activation from the structure of cephalosporin acylase: a protein with two proteolytic chemistries., Kim JK, Yang IS, Shin HJ, Cho KJ, Ryu EK, Kim SH, Park SS, Kim KH, Proc Natl Acad Sci U S A. 2006 Feb 7;103(6):1732-7. Epub 2006 Jan 30. PMID: 16446446

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