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A Salmonella Typhi homologue of bacteriophage muramidases controls typhoid toxin secretion
Author(s) -
Hodak Hélène,
Galán Jorge E
Publication year - 2013
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/embor.2012.186
Subject(s) - typhoid fever , salmonella typhi , bacteriophage , microbiology and biotechnology , secretion , salmonella , virology , toxin , biology , bacteria , escherichia coli , gene , genetics , biochemistry
Unlike other Salmonella , which can infect a broad range of hosts causing self‐limiting infection , Salmonella Typhi is an exclusively human pathogen that causes typhoid fever, a life‐threatening systemic disease. Typhoid toxin is a unique virulence factor of Salmonella Typhi, which is expressed when the bacteria are within mammalian cells. Here, we report that an N ‐acetyl‐β‐ D ‐muramidase similar to phage endolysins encoded within the same pathogenicity islet as the toxin is required for typhoid toxin secretion. Genetic and functional analysis of TtsA revealed unique amino acids at its predicted peptidoglycan‐binding domain that are essential for protein secretion and that distinguishes this protein from other homologues. We propose that TtsA defines a new protein secretion mechanism recently evolved from the machine that mediates phage release.