Sulfolobus turreted icosahedral virus 1 (formerly Sulfolobus turreted icosahedral virus) is a species of virus that infects the archaeon Sulfolobus solfataricus.
This virus was isolated from a hot spring in the Rabbit Creek thermal area which is located in the Midway Geyser Basin of Yellowstone National Park.
It is an icosahedrally symmetric virus with a unique triangulation number (T) of 31. At the 12 fivefold symmetrical positions of the icosahedron protrude 'turrets' that extend 13 nanometers (nm) above the capsid surface. The turrets have an average diameter of 24 nm. The center of each turret contains a ~3-nm channel.
There are five structural proteins: a major protein of 37 kilodaltons (kDa) and several minor proteins with estimated masses of 75, 25, 12.5 and 10 kDa. The major capsid protein is predominantly ò-sheeted.
The genome is circular double stranded DNA 17,663 base pairs in length with 36 open reading frames. The genome has a G+C content of 36%.
At the end of the infection cycle, virions leave the host cell by inducing host cell lysis and are released through pyramid-like structures that pierce through the S-layer of the cell envelope.