Mechanisms of substrate recognition by a typhoid toxin secretion-associated muramidase.

ABSTRACT: Typhoid toxin is a virulence factor for the bacterial pathogen Salmonella Typhi, which causes typhoid fever in humans. After its synthesis by intracellular bacteria, typhoid toxin is secreted into the lumen of the Salmonella-containing vacuole by a secretion mechanism strictly dependent on TtsA, a specific muramidase that facilitates toxin transport through the peptidoglycan layer. Here we show that substrate recognition by TtsA depends on a discrete domain within its carboxy terminus, which targets the enzyme to the bacterial poles to recognize YcbB-edited peptidoglycan. Comparison of the atomic structures of TtsA bound to its substrate and that of a close homolog with different specificity identified specific determinants involved in substrate recognition. Combined with structure-guided

SUBMITTER: Geiger T 

PROVIDER: S-EPMC6996933 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature