5C20:
reference: Optimize the interactions at S4 with efficient inhibitors targeting 3C proteinase from enterovirus 71., Zhang L, Huang G, Cai Q, Zhao C, Tang L, Ren H, Li P, Li N, Huang J, Chen X, Guan Y, You H, Chen S, Li J, Lin T, J Mol Recognit. 2016 May 17. doi: 10.1002/jmr.2551. PMID: 27185390

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