<b>Molecular and chemical characterization of the lipopolysaccharide O‐antigen and its role in the virulence of <i>Yersinia enterocolitica</i> serotype O:8</b>

Zhang, Lijuan; Radziejewska‐Lebrecht, Joanna; Krajewska-Pietrasik, D; Toivanen, Paavo; Skurnik, Mikael

doi:10.1046/j.1365-2958.1997.1871558.x

Cited by 137 publications

(132 citation statements)

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“…We demonstrated previously that both O-antigen and OC are essential for full virulence of Y. enterocolitica serotype O:3 (AlHendy, 1992; Skurnik et al, 1999), and O-antigen for serotype O:8 (Zhang et al, 1997). In mouse experiments, the oral LD 50 of the LPS mutants decreased 50-to 100-fold (Al-Hendy, 1992;Skurnik et al, 1999;Zhang et al, 1997).…”

Section: Discussionmentioning

confidence: 93%

“…In mouse experiments, the oral LD 50 of the LPS mutants decreased 50-to 100-fold (Al-Hendy, 1992;Skurnik et al, 1999;Zhang et al, 1997). The O-antigen of this pathogen plays a crucial role in the early stages of infection, and confers resistance to the environment of the gastrointestinal tract and to immune system evasion (Al-Hendy, 1992;Biedzka-Sarek et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…In Gram-negative bacteria, virulence and resistance to antimicrobial compounds depend on LPS Biedzka-Sarek et al, 2005;Reinés et al, 2012). In line with this, the O-antigen and OC are essential for full virulence of Y. enterocolitica O:3 and O:8, and loss of either of them leads to severe attenuation (Al-Hendy, 1992;Skurnik et al, 1999;Zhang et al, 1997).…”

Section: Introductionmentioning

confidence: 87%

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Expression of the Yersinia enterocolitica O:3 LPS O-antigen and outer core gene clusters is RfaH-dependent

Leskinen

Varjosalo

et al. 2015

Microbiology

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The antiterminator RfaH is required for the expression of LPS, capsule, haemolysin, exotoxin, haemin uptake receptor and F pilus. As these structures are critical for bacterial virulence, loss of RfaH usually leads to attenuation. Here, we inactivated the rfaH gene of Yersinia enterocolitica O:3 to study its role in this enteropathogen. RNA sequencing of the WT and DrfaH strain transcriptomes revealed that RfaH acted as a highly specific regulator that enhanced the transcription of the operons involved in biosynthesis of LPS O-antigen and outer core (OC), but did not affect the expression of enterobacterial common antigen. Interestingly, the transcriptome of the DrfaH strain was very similar to that of an O-antigen-negative mutant. This indicated that some of the changes seen in the DrfaH strain, such as the genes involved in outer membrane homeostasis or in the stress-response-associated Cpx pathway, were actually due to indirect responses via the loss of O-antigen. The decreased amount of LPS on the DrfaH strain cell surface resulted in an attenuated stress response, and lower resistance to compounds such as SDS and polymyxin B. However, the DrfaH strain was significantly more resistant to complement-mediated killing by normal human serum. Taken together, our results revealed a novel role of RfaH acting as a highly specific regulator of O-antigen and OC of LPS in Y. enterocolitica O:3. It may be speculated that RfaH might have an in vivo role in controlling tissue-specific expression of bacterial surface oligo/polysaccharides.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

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Expression of the Yersinia enterocolitica O:3 LPS O-antigen and outer core gene clusters is RfaH-dependent

Leskinen

Varjosalo

et al. 2015

Microbiology

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“…The analysis of WecA mutant proteins containing amino acid replacements of these key residues strongly suggests their involvement in the recognition of UDP-GlcNAc. Since WecA can also complement the biosynthesis of O antigens containing N-acetylgalactosamine, other investigators have suggested that WecA has a loose substrate specificity, which involves the recognition of UDP-N-acetylgalactosamine in addition to UDP-GlcNAc (Amor & Whitfield, 1997 ;Zhang et al, 1997). Future studies involving purified WecA, currently under way in our laboratory, are needed to clarify its substrate specificity.…”

Section: Discussionmentioning

confidence: 97%

Conserved amino acid residues found in a predicted cytosolic domain of the lipopolysaccharide biosynthetic protein WecA are implicated in the recognition of UDP-N-acetylglucosamine

Amer¹,

Valvano²

2001

Microbiology

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“…PCP1a proteins have N-terminal and C-terminal transmembrane helices (TM1 and TM2) which flank a periplasmic polypeptide segment that contains predicted coiled-coil regions. LPS Oag modal chain length regulation has an important role in the pathogenesis of different bacteria (al-Hendy et al, 1992;Crawford et al, 2012;Hong & Payne, 1997;Kintz et al, 2008;Murray et al, 2003Murray et al, , 2005Najdenski et al, 2003;Van den Bosch et al, 1997;Van den Bosch & Morona, 2003;Zhang et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Residues located inside the Escherichia coli FepE protein oligomer are essential for lipopolysaccharide O-antigen modal chain length regulation

Tran

Morona

2013

Microbiology

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The Escherichia coli O157 : H7 FepE protein regulates lipopolysaccharide (LPS) O-antigen (Oag) chain length to confer a very long modal chain length of .80 Oag repeat units (RUs). The mechanism by which FepE regulates Oag modal chain length and the regions within it that are important for its function remain unclear. Studies on the structure of FepE show that the protein oligomerizes. However, the exact size of the oligomer is in dispute, further hampering our understanding of its mechanism. Guided by information previously obtained for regions known to be important for Oag modal chain length determination in the homologous Shigella flexneri WzzB SF protein, a set of FepE mutant constructs with single amino acid substitutions was created. Analysis of the resulting LPS conferred by these mutant His 6 -FepE proteins showed that amino acid substitutions of leucine 168 (L168) and aspartic acid 268 (D268) resulted in LPS with consistently shortened Oag chain lengths of ,80 Oag RUs. Substitution of FepE's transmembrane cysteine residues did not affect function. Chemical cross-linking experiments on mutant FepE proteins showed no consistent correlation between oligomer size and functional activity, and MS analysis of FepE oligomers indicated that the in vivo size of FepE is consistent with a maximum size of a hexamer. Our findings suggest that different FepE residues, mainly located within the internal cavity of the oligomer, contribute to Oag modal chain length determination but not the oligomeric state of the protein. INTRODUCTIONLipopolysaccharide (LPS) is an important virulence factor of many Gram-negative bacteria and generally consists of three distinct regions: the membrane-anchored lipid A domain, the core sugar region and the O-antigen (Oag) polysaccharide chains (Raetz & Whitfield, 2002). In Shigella flexneri, as well as in other members of the family Enterobacteriaceae, the genes encoding enzymes for Oag biosynthesis and polymerization are mainly found in the bacterial chromosome, but can also be plasmid-encoded (Raetz & Whitfield, 2002). Oag is a polymer of sugar repeat units (RUs) which define the Oag serotype specificity. The basic Oag RU of S. flexneri is a tetrasaccharide made up of three rhamnose sugars and one N-acetylglucosamine sugar.The following describes the Oag synthesis strategy in S. flexneri and Escherichia coli K-12 known as the Wzydependent polymerization pathway (Morona et al., 2009;Raetz & Whitfield, 2002;Samuel & Reeves, 2003;Tocilj et al., 2008). Biosynthesis of the Oag is initiated on the cytoplasmic side of the inner membrane. After a series of successive glycoyltransferase reactions, an RU is assembled on the membrane-bound carrier undecaprenyl pyrophosphate (Und-PP) and is then transferred across to the periplasmic side of the membrane by the Wzx flippase. Oag RUs then undergo polymerization by the Wzy polymerase and are attached on to the lipid A-core molecule by the WaaL ligase to form a chain of Oag RUs on a complete LPS molecule. Oag RUs can vary considerably from 0 to .100 in n...

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**Molecular and chemical characterization of the lipopolysaccharide O‐antigen and its role in the virulence of Yersinia enterocolitica serotype O:8**

Cited by 137 publications

References 40 publications

Expression of the Yersinia enterocolitica O:3 LPS O-antigen and outer core gene clusters is RfaH-dependent

Expression of the Yersinia enterocolitica O:3 LPS O-antigen and outer core gene clusters is RfaH-dependent

Conserved amino acid residues found in a predicted cytosolic domain of the lipopolysaccharide biosynthetic protein WecA are implicated in the recognition of UDP-N-acetylglucosamine

Residues located inside the Escherichia coli FepE protein oligomer are essential for lipopolysaccharide O-antigen modal chain length regulation

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