Demarcating SurA activities required for outer membrane targeting of Yersinia pseudotuberculosis adhesins

• SurA is a periplasmic protein folding factor involved in chaperoning and trafficking of outer membrane proteins across the Gram-negative bacterial periplasm. In addition, SurA also possesses peptidyl-prolyl cis/trans isomerase activity. In enteropathogenic Yersinia pseudotuberculosis, we have previously reported that SurA is needed for bacterial virulence and envelope integrity. In this study, we investigated the role of SurA in the assembly of important Yersinia adhesins. Using genetic mutation, biochemical characterization and an in vitro-based bacterial host cell association assay, we confirmed that surface localization of the invasin adhesin is dependent on SurA. As a surA deletion also has some impact on the levels of individual components of the BAM complex in the Yersinia outer membrane, abolished invasin surface assembly could reflect both a direct loss of SurA-dependent periplasmic targeting as well as a potentially compromised BAM complex assembly platform in the outer membrane. To varying degrees, the assembly of two other adhesins, Ail and the pH 6 antigen fibrillum PsaA also depend on SurA. Consequently, loss of SurA leads to a dramatic reduction in Yersinia attachment to eukaryotic host cells. Genetic complementation of surA deletion mutants indicated a prominent role for SurA chaperone function in outer membrane protein assembly. Significantly, the N-terminus of SurA contributed most of this SurA chaperone function. Despite a dominant chaperoning role, it was also evident that SurA isomerization activity did make a modest contribution to this assembly process.

Ämnesord

NATURVETENSKAP  -- Biologi -- Mikrobiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Microbiology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

outer membrane proteins

chaperone

peptidyl-prolyl cis/trans isomerase

OmpA

type three secretion

mikrobiologi

Microbiology

Infectious Diseases

infektionssjukdomar

molekylärbiologi

Molecular Biology

Biochemistry

biokemi

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