Download MendeleyMechanisms of substrate recognition by a typhoid toxin secretion-associated muramidase.
Geiger, T., Lara-Tejero, M., Xiong, Y., Galan, J.E.(2020) Elife 9
- PubMed: 31958059 Search on PubMedSearch on PubMed Central
- DOI: https://doi.org/10.7554/eLife.53473
- Primary Citation Related Structures:
6V3Z, 6V40 - PubMed 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 mutagenesis and in vitro and in vivo crosslinking experiments, this study provides an unprecedented view of the mechanisms by which a muramidase recognizes its peptidoglycan substrate to facilitate protein secretion.
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.
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