Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4-
            <i>O</i>
            -Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

Wang, Jianping; Lan, Ruiting; Knirel, Yuriy A.; Luo, Xia; Senchenkova, Sof’ya N.; Shashkov, Alexander S.; Xu, Jianguo; Sun, Qiang

doi:10.1128/jcm.00197-14

Cited by 9 publications

(22 citation statements)

References 36 publications

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“…In various S. flexneri serotypes, the same monosaccharide may carry different chemical groups; for instance, a glucosyl, O-acetyl, or PEtN group is attached at position 3 of Rha III in serotypes X, 1, and 4av, giving rise to O-factors 7,8, O-factor 9, and O-factor IV-1, respectively (8,20,29). Earlier, we demonstrated that the 3-glycosyl group on Rha III in serotype 2b and X strains can be completely or (in serotype X) almost completely replaced with the 3-or 4-O-acetyl group (28) upon transformation with the oacB gene for the specific acetyltransferase.…”

Section: Discussionmentioning

confidence: 99%

“…Immunization and preparation of antisera were performed as described previously (29,35). Briefly, three New Zealand White rabbits (female, 1.5 to 2 kg body weight) were immunized intravenously with heat-killed cells of S. flexneri strain Sf301 twice a week at increasing doses (1 ϫ 10 9 , 2 ϫ 10 9 , 4 ϫ 10 9 , 8 ϫ 10 9 , 16 ϫ 10 9 , and 16 ϫ 10 9 CFU).…”

Section: Methodsmentioning

confidence: 99%

“…The serological features of S. flexneri strains were revealed by a slide agglutination test using commercially available Shigella monovalent antisera (Denka Seiken, Japan) and monoclonal antibody (Reagensia AB, Sweden), as well as 3/4-O-acetylated Rha III -specific antiserum 9 prepared previously (29). Antiserum 10 prepared in this study was used for detection of the 6-O-acetylated GlcNAc-linked epitope by slide agglutination, and agglutination apparent to the naked eye within 20 s was recorded as representing a positive result.…”

Section: Methodsmentioning

confidence: 99%

“…The LPSs were electrophoresed on 15% polyacrylamide gels and detected by silver staining as described previously (36,37). A Western blot assay of the LPS was performed as described previously (29). The LPS separated by SDS-PAGE was transferred onto a polyvinylidene difluoride (PVDF) membrane and incubated with antiserum 10.…”

Section: Methodsmentioning

confidence: 99%

“…Further studies have indicated that an acyltransferase protein (OacB) which is encoded by gene oacB carried on a transposon-like element of the chromosome mediates the 3/4-O-acetylation in serotypes 1a, 1b, 2a, 5a, and Y (28), whereas an OacB homolog named OacC encoded by a phage-like structure is responsible for the 3/4-O-acetylation in serotype 6 (see the supplemental material). The oacB and oacC genes are widespread in serotypes 1a, 1b, 2a, 5a, Y, and 6 and confer to the host a novel antigenic determinant called group O-factor 9 (29). oacB and oacC are not involved with the 6-O-acetylation on GlcNAc as they could not be detected in strains carrying only this modification and their inactivation in strains carrying both 3/4-O-acetylation and 6-O-acetylation did not affect the 6-O-acetylation on GlcNAc (28) (see the supplemental material).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Serotype-Converting Bacteriophage SfII Encodes an Acyltransferase Protein That Mediates 6-O-Acetylation of GlcNAc in Shigella flexneri O-Antigens, Conferring on the Host a Novel O-Antigen Epitope

Sun¹,

Knirel²,

Wang³

et al. 2014

Journal of Bacteriology

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Serotype-Converting Bacteriophage SfII Encodes an Acyltransferase Protein That Mediates 6-O-Acetylation of GlcNAc in Shigella flexneri O-Antigens, Conferring on the Host a Novel O-Antigen Epitope

Sun¹,

Knirel²,

Wang³

et al. 2014

Journal of Bacteriology

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A novel fold for acyltransferase-3 (AT3) proteins provides a framework for transmembrane acyl-group transfer

Newman

Tindall

Mader

et al. 2022

Preprint

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Acylation of diverse carbohydrates occurs across all domains of life and can be catalysed by proteins with a membrane bound acyltransferase-3 (AT3) domain (PF01757). In bacteria, these proteins are essential in processes including symbiosis, resistance to viruses and antimicrobials, and biosynthesis of antibiotics, yet their structure and mechanism is largely unknown. In this study, evolutionary co-variance analysis was used to build a computational model of the structure of a bacterial O-antigen modifying acetyltransferase, OafB. The resulting structure exhibited a novel fold for the AT3 domain, which molecular dynamics simulations demonstrated is stable in the membrane. The AT3 domain contains 10 transmembrane helices arranged to form a large cytoplasmic cavity lined by residues known to be essential for function. Further molecular dynamics simulations support a model where the acyl-coA donor spans the membrane through accessing a pore created by movement of an important loop capping the inner cavity, enabling OafB to present the acetyl group close to the likely catalytic resides on the extracytoplasmic surface. Limited but important interactions with the fused SGNH domain in OafB are identified and modelling suggests this domain is mobile and can both accept acyl-groups from the AT3 and then reach beyond the membrane to reach acceptor substrates. Together this new general model of AT3 function provides a framework for the development of inhibitors that could abrogate critical functions of bacterial pathogens.

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Influence of Shigella flexneri 2a O Antigen Acetylation on Its Bacteriophage Sf6 Receptor Activity and Bacterial Interaction with Human Cells

et al. 2020

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Shigella flexneri is a major causative agent of bacillary dysentery in developing countries where serotype 2a2 is the prevalent strain. To date, approximately 30 serotypes have been identified for S. flexneri and the major contribution to the emergence of new serotypes is chemical modifications of the lipopolysaccharide (LPS) component O antigen (Oag). Glucosylation, O-acetylation and phosphoethanolamine (PEtN) modifications increase the Oag diversity providing benefits to S. flexneri. LPS Oag acts as a primary receptor for bacteriophage Sf6, which only infects a limited range of S. flexneri serotypes (Y, X). It uses its tailspike protein (Sf6TSP) to establish initial interaction with LPS Oags that it then hydrolyses. Currently, there is a lack of comprehensive study on the parent and serotype variant strains from the same genetic background and the understanding of the importance of LPS Oag O-acetylations. Therefore, a set of isogenic strains [based on S. flexneri 2457T (2a2)] with deletions of different Oag modification genes (oacB, oacD and gtrII) that resemble different naturally occurring serotype Y and 2a strains was created. The impact of these Oag modifications on S. flexneri sensitivity to Sf6 and the pathogenesis-related properties were then compared. We found that Sf6TSP can hydrolyse serotype 2a LPS Oag, identified that 3/4-O-acetylation is essential for resistance of serotype 2a strains to Sf6, and showed that serotype 2a strains have better invasion ability. Lastly, we revealed two new serotype conversions for S. flexneri thereby contributing to understanding the evolution of this important human pathogen. Importance The emergence of antibiotic resistance strains and lack of efficient vaccines have made Shigella a priority organism for the World Health Organisation (1). Therefore, bacteriophage therapy has received increasing attention as an alternative therapeutic approach. LPS Oag is the most variable part of LPS due to chemical modifications and is the target of bacteriophage Sf6 (S. flexneri-specific). We dissected the evolution of S. flexneri serotype Y to 2a2, which revealed a new role for a gene acquired during serotype conversion and furthermore identified new specific forms of LPS receptor for Sf6. Collectively, these results unfold the importance of the acquisition of those Oag modification genes and further our understanding of the relationship between Sf6 and S. flexneri.

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Serological Identification and Prevalence of a Novel O-Antigen Epitope Linked to 3- and 4- O -Acetylated Rhamnose III of Lipopolysaccharide in Shigella flexneri

Cited by 9 publications

References 36 publications

Serotype-Converting Bacteriophage SfII Encodes an Acyltransferase Protein That Mediates 6-O-Acetylation of GlcNAc in Shigella flexneri O-Antigens, Conferring on the Host a Novel O-Antigen Epitope

Serotype-Converting Bacteriophage SfII Encodes an Acyltransferase Protein That Mediates 6-O-Acetylation of GlcNAc in Shigella flexneri O-Antigens, Conferring on the Host a Novel O-Antigen Epitope

A novel fold for acyltransferase-3 (AT3) proteins provides a framework for transmembrane acyl-group transfer

Influence of Shigella flexneri 2a O Antigen Acetylation on Its Bacteriophage Sf6 Receptor Activity and Bacterial Interaction with Human Cells

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