Anchoring the T6SS to the Cell Wall: Crystal Structure of the Peptidoglycan Binding Domain of the TagL Accessory Protein

Van Son Nguyen , Silvia Spinelli , Éric Cascales , Alain Roussel , Christian Cambillau , Philippe Leone (1)

1 AFMB - Architecture et fonction des macromolécules biologiques

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 2 different cellular functions rely on an interaction network with peptidoglycan strictly conserved.

Mots clés: Type VI secretion; Peptidoglycan; cell wall; membrane complex

Domaines: Cristallographie; Biologie structurale [q-bio.BM]

Van Son Nguyen, Silvia Spinelli, Éric Cascales, Alain Roussel, Christian Cambillau, et al.. Anchoring the T6SS to the Cell Wall: Crystal Structure of the Peptidoglycan Binding Domain of the TagL Accessory Protein. PLoS ONE, 2021. ⟨hal-03358248⟩