2C0N VIRAL PROTEIN/TRANSFERASE, VIRAL PROTEIN, VIRUS, ARCHAEA, CRENARCHAEA, ARCHAEAL VIRUS, CRENARCHAEAL VIRUS, THERMOPHILIC PROTEIN, THERMOPHILIC VIRUS, STIV, SULFOLOBUS TURRETED ICOSAHEDRAL VIRUS, SULFOLOBUS, GLYCOSYLTRANSFERASE, TRANSFERASE CRYSTAL STRUCTURE OF A197 FROM STIV