3QTL:
reference: Structural basis for dual-inhibition mechanism of a non-classical kazal-type serine protease inhibitor from horseshoe crab in complex with subtilisin., Shenoy RT, Thangamani S, Velazquez-Campoy A, Ho B, Ding JL, Sivaraman J, PLoS One. 2011 Apr 26;6(4):e18838. PMID: 21541315

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