ATP-independent control of autotransporter virulence protein transport via the folding properties of the secreted protein.

ABSTRACT: Autotransporter (AT) proteins are the largest class of extracellular virulence proteins secreted from Gram-negative bacteria. The mechanism by which AT proteins cross the bacterial outer membrane (OM), in the absence of ATP or another external energy source, is unknown. Here we demonstrate a linear correlation between localized regions of stability (?G(folding)) in the mature virulence protein (the AT "passenger") and OM secretion efficiency. Destabilizing the C-terminal ?-helical domain of a passenger reduced secretion efficiency. In contrast, destabilizing the globular N-terminal domain of a passenger produced a linearly correlated increase in secretion efficiency. Thus, C-terminal passenger stability facilitates OM secretion, whereas N-terminal stability hinders it. The contributions of regional passenger stability to OM secretion demonstrate a crucial role for the passenger itself in directing its secretion, suggesting a novel type of ATP-independent, folding-driven transporter.

SUBMITTER: Renn JP 

PROVIDER: S-EPMC3288764 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature