Open AccessAnchoring the T6SS to the cell wall: Crystal structure of the peptidoglycan binding domain of the TagL accessory protein
Author(s) -
Van Son Nguyen,
S. Spinelli,
Eric Cascalès,
Alain Roussel,
Christian Cambillau,
Philippe Leone
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0254232
Subject(s) - peptidoglycan , cell envelope , type vi secretion system , microbiology and biotechnology , bacterial cell structure , biology , cell wall , flagellum , secretion , plasma protein binding , cell , protein structure , biochemistry , bacteria , virulence , gene , genetics , escherichia coli
The type VI secretion system (T6SS) is a widespread mechanism of protein delivery into target cells, present in more than a quarter of all sequenced Gram-negative bacteria. The T6SS constitutes an important virulence factor, as it is responsible for targeting effectors in both prokaryotic and eukaryotic cells. The T6SS comprises a tail structure tethered to the cell envelope via a trans-envelope complex. In most T6SS, the membrane complex is anchored to the cell wall by the TagL accessory protein. In this study, we report the first crystal structure of a peptidoglycan-binding domain of TagL. The fold is conserved with members of the OmpA/Pal/MotB family, and more importantly, the peptidoglycan binding site is conserved. This structure further exemplifies how proteins involved in anchoring to the cell wall for different cellular functions rely on an interaction network with peptidoglycan strictly conserved.