2YKL:
reference: Different binding modes of free and carrier-protein-coupled nicotine in a human monoclonal antibody., Tars K, Kotelovica S, Lipowsky G, Bauer M, Beerli RR, Bachmann MF, Maurer P, J Mol Biol. 2012 Jan 6;415(1):118-27. Epub 2011 Nov 3. PMID: 22079050

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