2XP1:
reference: Noncanonical tandem SH2 enables interaction of elongation factor Spt6 with RNA polymerase II., Diebold ML, Loeliger E, Koch M, Winston F, Cavarelli J, Romier C, J Biol Chem. 2010 Dec 3;285(49):38389-98. Epub 2010 Oct 6. PMID: 20926373

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