Structure of a Rhs effector clade domain provides mechanistic insights into type VI secretion system toxin delivery.

ABSTRACT: The type VI secretion system (T6SS) is a molecular machine utilised by many Gram-negative bacteria to deliver antibacterial toxins into adjacent cells. Here we present the structure of Tse15, a T6SS Rhs effector from the nosocomial pathogen Acinetobacter baumannii. Tse15 forms a triple layered β-cocoon Rhs domain with an N-terminal α-helical clade domain and an unfolded C-terminal toxin domain inside the Rhs cage. Tse15 is cleaved into three domains, through independent auto-cleavage events involving aspartyl protease activity for toxin self-cleavage and a nucleophilic glutamic acid for N-terminal clade cleavage. Proteomic analyses identified that significantly more peptides from the N-terminal clade and toxin domains were secreted than from the Rhs cage, suggesting toxin delivery often oc

SUBMITTER: Hayes BK 

PROVIDER: S-EPMC11461821 | biostudies-literature | 2024 Oct

REPOSITORIES: biostudies-literature