4KDV:
reference: Role of Ca in folding the tandem beta-sandwich extender domains of a bacterial ice-binding adhesin., Guo S, Garnham CP, Karunan SP, Campbell RL, Allingham JS, Davies PL, FEBS J. 2013 Sep 11. doi: 10.1111/febs.12518. PMID: 24024640

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