2C4S:
reference: Calcium chondroitin 4-sulfate: molecular conformation and organization of polysaccharide chains in a proteoglycan., Cael JJ, Winter WT, Arnott S, J Mol Biol 1978 Oct 15;125(1):21-42. PMID: 712856

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