DsbA Is Required for Stable Expression of Outer Membrane Protein YscC and for Efficient Yop Secretion inYersinia pestis

ABSTRACT The role of the periplasmic disulfide oxidoreductase DsbA in Yop secretion was investigated in Yersinia pestis. A Y. pestis dsbA mutant secreted reduced amounts of the V antigen and Yops and expressed reduced amounts of the full-sized YscC protein. Site-directed mutagenesis of the four cysteine residues present in the YscC protein resulted in defects similar to those found in thedsbA mutant. These results suggest that YscC contains at least one disulfide bond that is essential for the function of this protein in Yop secretion.

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Resistance of Yersinia pestis to Complement-Dependent Killing Is Mediated by the Ail Outer Membrane Protein

Infection and Immunity ◽

10.1128/iai.01125-07 ◽

2007 ◽

Vol 76 (2) ◽

pp. 612-622 ◽

Cited By ~ 102

Author(s):

Sara Schesser Bartra ◽

Katie L. Styer ◽

Deanna M. O'Bryant ◽

Matthew L. Nilles ◽

B. Joseph Hinnebusch ◽

...

Keyword(s):

Membrane Protein ◽

Yersinia Pestis ◽

Outer Membrane ◽

Outer Membrane Protein ◽

Pathogenic Bacteria ◽

Outer Membrane Proteins ◽

Mouse Serum ◽

Bacterial Killing ◽

High Level

ABSTRACT Yersinia pestis, the causative agent of plague, must survive in blood in order to cause disease and to be transmitted from host to host by fleas. Members of the Ail/Lom family of outer membrane proteins provide protection from complement-dependent killing for a number of pathogenic bacteria. The Y. pestis KIM genome is predicted to encode four Ail/Lom family proteins. Y. pestis mutants specifically deficient in expression of each of these proteins were constructed using lambda Red-mediated recombination. The Ail outer membrane protein was essential for Y. pestis to resist complement-mediated killing at 26 and 37°C. Ail was expressed at high levels at both 26 and 37°C, but not at 6°C. Expression of Ail in Escherichia coli provided protection from the bactericidal activity of complement. High-level expression of the three other Y. pestis Ail/Lom family proteins (the y1682, y2034, and y2446 proteins) provided no protection against complement-mediated bacterial killing. A Y. pestis ail deletion mutant was rapidly killed by sera obtained from all mammals tested except mouse serum. The role of Ail in infection of mice, Caenorhabditis elegans, and fleas was investigated.

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Outer Membrane Protein X (Ail) Contributes to Yersinia pestis Virulence in Pneumonic Plague and Its Activity Is Dependent on the Lipopolysaccharide Core Length

Infection and Immunity ◽

10.1128/iai.00783-10 ◽

2010 ◽

Vol 78 (12) ◽

pp. 5233-5243 ◽

Cited By ~ 49

Author(s):

Anna M. Kolodziejek ◽

Darren R. Schnider ◽

Harold N. Rohde ◽

Andrzej J. Wojtowicz ◽

Gregory A. Bohach ◽

...

Keyword(s):

Membrane Protein ◽

Yersinia Pestis ◽

Outer Membrane ◽

Rat Model ◽

Outer Membrane Protein ◽

Serum Resistance ◽

Wild Type ◽

Time To Death ◽

Protein X

ABSTRACT Yersinia pestis, the causative agent of plague, is one of the most virulent microorganisms known. The outer membrane protein X (OmpX) in Y. pestis KIM is required for efficient bacterial adherence to and internalization by cultured HEp-2 cells and confers resistance to human serum. Here, we tested the contribution of OmpX to disease progression in the fully virulent Y. pestis CO92 strain by engineering a deletion mutant and comparing its ability in mediating pneumonic plague to that of the wild type in two animal models. The deletion of OmpX delayed the time to death up to 48 h in a mouse model and completely attenuated virulence in a rat model of disease. All rats challenged with 1 × 108 CFU of the ompX mutant survived, compared to the 50% lethal dose (LD50) of 1.2 × 103 CFU for the wild-type strain. Because murine serum is not bactericidal for the ompX mutant, the mechanism underlying the delay in time to death in mice was attributed to loss of adhesion/internalization properties but not serum resistance. The rat model, which is most similar to humans, highlighted the critical role of serum resistance in disease. To resolve conflicting evidence for the role of Y. pestis lipopolysaccharide (LPS) and OmpX in serum resistance, ompX was cloned into Escherichia coli D21 and three isogenic derivatives engineered to have progressively truncated LPS core saccharides. OmpX-mediated serum resistance, adhesiveness, and invasiveness, although dependent on LPS core length, displayed these functions in E. coli, independently of other Yersinia proteins and/or LPS. Also, autoaggregation was required for efficient OmpX-mediated adhesiveness and internalization but not serum resistance.

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