1F2X:
reference: Canonical antigen-binding loop structures in immunoglobulins: more structures, more canonical classes?, Decanniere K, Muyldermans S, Wyns L, J Mol Biol 2000 Jun 30;300(1):83-91. PMID: 10864500

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