2WUR:
reference: Visualizing proton antenna in a high-resolution green fluorescent protein structure., Shinobu A, Palm GJ, Schierbeek AJ, Agmon N, J Am Chem Soc. 2010 Aug 18;132(32):11093-102. PMID: 20698675

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