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An alternative outer membrane secretion mechanism for an autotransporter protein lacking a C ‐terminal stable core
Author(s) -
Besingi Richard N.,
Chaney Julie L.,
Clark Patricia L.
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12414
Subject(s) - secretion , biology , virulence , yersinia , bacterial outer membrane , microbiology and biotechnology , biochemistry , bacteria , escherichia coli , genetics , gene
Summary Autotransporter ( AT ) proteins are a broad class of virulence factors from Gram‐negative pathogens. AT outer membrane ( OM ) secretion appears simple in many regards, yet the mechanism that enables transport of the central AT ‘passenger’ across the OM remains unclear. OM secretion efficiency for two AT passengers is enhanced by a ∼ 20 kDa stable core at the C ‐terminus of the passenger, but studies on a broader range of AT proteins are needed in order to determine whether a stability difference between the passenger N ‐ and C ‐terminus represents a truly common mechanistic feature. Y ersinia pestis YapV is homologous to S higella flexneri IcsA , and like IcsA , YapV recruits mammalian neural W iskott– A ldrich syndrome protein ( N ‐ WASP ). In vitro , the purified YapV passenger is functional and rich in β‐sheet structure, but lacks a ∼ 20 kDa C ‐terminal stable core. However, the N ‐terminal 49 residues of the YapV passenger globally destabilize the entire YapV passenger, enhancing its OM secretion efficiency. These results indicate that the contributions of AT passenger sequences to OM secretion efficiency extend beyond a C ‐terminal stable core, and highlight a role of the passenger N ‐terminus in reducing passenger stability in order to facilitate OM secretion of some AT proteins.