1CT4:
reference: Deleterious effects of beta-branched residues in the S1 specificity pocket of Streptomyces griseus proteinase B (SGPB): crystal structures of the turkey ovomucoid third domain variants Ile18I, Val18I, Thr18I, and Ser18I in complex with SGPB., Bateman KS, Anderson S, Lu W, Qasim MA, Laskowski M Jr, James MN, Protein Sci 2000 Jan;9(1):83-94. PMID: 10739250

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