The sulfolobus turreted icosahedral virus (STIV) infects Sulfolobus species found in the hot springs of Yellowstone National Park. It has 37 ORFs including B116, whose function is unknown. The structure of B116 reveals a fold consisting of a five-stranded beta-sheet flanked on one side by three alpha helices. Two subunits come together to form a homodimer with a 10-stranded mixed beta-sheet, where the topology of the central strands resembles an unclosed beta-barrel [1].

1: A new DNA binding protein highly conserved in diverse crenarchaeal viruses. Larson ET, Eilers BJ, Reiter D, Ortmann AC, Young MJ, Lawrence CM; Virology. 2007;363:387-396. PMID:17336360