2YQY:
reference: Crystal structure of TTHA0303 (TT2238), a four-helix bundle protein with an exposed histidine triad from Thermus thermophilus HB8 at 2.0 A., Nagata K, Ohtsuka J, Takahashi M, Asano A, Iino H, Ebihara A, Tanokura M, Proteins. 2008 Feb 15;70(3):1103-7. PMID: 18004771

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