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Volume 153, Issue 11

Biochemical characterization of the enterotoxigenic LeoA protein Free

Abstract

Enterotoxigenic (ETEC) causes enterotoxin-induced diarrhoea and significant mortality. The molecular mechanisms underlying how the heat-labile enterotoxin (LT) is secreted during infection are poorly understood. ETEC produce outer-membrane vesicles (OMVs) containing LT that are endocytosed into host cells. Although OMV production and protein content may be a regulated component of ETEC pathogenesis, how LT loading into OMVs is regulated is unknown. The LeoA protein plays a role in secreting LT from the bacterial periplasm. To begin to understand the function of LeoA and its role in ETEC H10407 pathogenesis, a site-directed mutant lacking the putative GTP-binding domain was constructed. The ability of wild-type and mutant LeoA to hydrolyse GTP was quantified. This domain was found to be responsible for GTP binding; it is important to LeoA's function in LT secretion, and may play a modest role in the formation and protein content of OMVs. Deletion of reduced the abundance of OmpX in outer-membrane protein preparations and of LT in OMVs. Immunoprecipitation experiments revealed that LeoA interacts directly with OmpA, but that the GTP-binding domain is non-essential for this interaction. Deletion of rendered ETEC H10407 non-motile, through apparent periplasmic accumulation of FliC.

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Keyword(s): ETEC, enterotoxigenic Escherichia coli , LT, heat-labile enterotoxin , OMP, outer-membrane protein , OMV, outer-membrane vesicle and wt, wild-type
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2007-11-01
2024-04-19
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Biochemical characterization of the enterotoxigenic Escherichia coli LeoA protein
Microbiology 153, 3776 (2007); https://doi.org/10.1099/mic.0.2007/009084-0
/content/journal/micro/10.1099/mic.0.2007/009084-0
/content/journal/micro/10.1099/mic.0.2007/009084-0
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