Engelsk definition
Multiprotein complexes in GRAM NEGATIVE BACTERIA that deliver effector proteins into eukaryotic or prokaryotic cells by a mechanism similar to the contractile tail of bacteriophages. They are composed of a cell envelope-spanning tube which is surrounded by a contractile sheath and tipped by a cell puncturing complex; a base plate structure that anchors the assembly to the cell envelope; and an ATPase involved in the sheath contraction and disassembly of the complex.