1XF1:
reference: Structure of the streptococcal cell wall C5a peptidase., Brown CK, Gu ZY, Matsuka YV, Purushothaman SS, Winter LA, Cleary PP, Olmsted SB, Ohlendorf DH, Earhart CA, Proc Natl Acad Sci U S A. 2005 Dec 20;102(51):18391-6. Epub 2005 Dec 12. PMID: 16344483

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