Structural characteristics of the plasmid-encoded toxin from enteroaggregative Escherichia coli.

ABSTRACT: Intoxication by the plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coli requires toxin translocation from the endoplasmic reticulum (ER) to the cytosol. This event involves the quality control system of ER-associated degradation (ERAD), but the molecular details of the process are poorly characterized. For many structurally distinct AB-type toxins, ERAD-mediated translocation is triggered by the spontaneous unfolding of a thermally unstable A chain. Here we show that Pet, a non-AB toxin, engages ERAD by a different mechanism that does not involve thermal unfolding. Circular dichroism and fluorescence spectroscopy measurements demonstrated that Pet maintains most of its secondary and tertiary structural features at 37 degrees C, with significant thermal unfolding only occurrin

SUBMITTER: Scaglione P 

PROVIDER: S-EPMC2551761 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature