RT Journal Article
SR Electronic
T1 VipA N-terminal linker and VipB-VipB interaction modulate the contraction of Type VI secretion system sheath
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 152785
DO 10.1101/152785
A1 Maximilian Brackmann
A1 Jing Wang
A1 Marek Basler
YR 2017
UL http://biorxiv.org/content/early/2017/06/21/152785.abstract
AB Secretion systems are essential for bacteria to survive and manipulate their environment. The bacterial Type VI Secretion System (T6SS) generates the force needed for protein translocation by the contraction of a long polymer called sheath, which is composed of interconnected VipA/VipB subunits forming a six-start helix. The mechanism of T6SS sheath contraction and the structure of its extended state are unknown. Here we show that elongating the N-terminal VipA linker or eliminating charge of a specific VipB residue abolished sheath contraction and delivery of effectors into target cells. The assembly of the non-contractile sheaths was dependent on the baseplate component TssE and mass-spectrometry analysis identified Hcp, VgrG and other components of the T6SS baseplate specifically associated with stable non-contractile sheaths. The ability to lock T6SS in the pre-firing state opens new possibilities for understanding its mode of action.