Topological Investigation of Glucosyltransferase V in <i>Shigella flexneri</i> using the Substituted Cysteine Accessibility Method

Rusden, Anthony D.; Stephenson, David P.; Verma, Naresh K.

doi:10.1021/bi400168h

Cited by 6 publications

(2 citation statements)

References 38 publications

(90 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Gtr(type) enzymes are inte gral membrane proteins consisting of 8 10 transmem brane helices with the active sites located in the large periplasmic loops at the N and C termini. They have weak similarity to other known glucosyltransferase fami lies and are predicted to be members of the GT C super family, which utilize a phospholipid activated donor sugar substrate [47].…”

Section: Genetic Basis Of O Antigen Modifications and Resultant Serot...mentioning

confidence: 99%

O-Antigen modifications providing antigenic diversity of Shigella flexneri and underlying genetic mechanisms

Knirel

Sun

Senchenkova

et al. 2015

Biochemistry Moscow

View full text Add to dashboard Cite

O-Antigens (O-specific polysaccharides) of Shigella flexneri, a primary cause of shigellosis, are distinguished by a wide diversity of chemical modifications following the oligosaccharide O-unit assembly. The present review is devoted to structural, serological, and genetic aspects of these modifications, including O-acetylation and phosphorylation with phosphoethanolamine that have been identified recently. The modifications confer the host with specific immunodeterminants (O-factors or O-antigen epitopes), which accounts for the antigenic diversity of S. flexneri considered as a virulence factor of the pathogen. Totally, 30 O-antigen variants have been recognized in these bacteria, the corresponding O-factors characterized using specific antibodies, and a significant extension of the serotyping scheme of S. flexneri on this basis is suggested. Multiple genes responsible for the O-antigen modifications and the resultant serotype conversions of S. flexneri have been identified. The genetic mechanisms of the O-antigen diversification by acquisition of mobile genetic elements, including prophages and plasmids, followed occasionally by gene mobilization and inactivation have been revealed. These findings further our understanding of the genetics and antigenicity of S. flexneri and assist control of shigellosis.

show abstract

Section: Genetic Basis Of O Antigen Modifications and Resultant Serot...mentioning

confidence: 99%

O-Antigen modifications providing antigenic diversity of Shigella flexneri and underlying genetic mechanisms

Knirel

Sun

Senchenkova

et al. 2015

Biochemistry Moscow

View full text Add to dashboard Cite

show abstract

“…The supernatant was discarded, and the pellet was resuspended in 200 μl of Buffer A (50 mM Tris-HCl, (pH 8.0) containing 100 mM NaCl. The membrane protein samples were used immediately or stored at − 80 °C [ 12 ].…”

Section: Methodsmentioning

confidence: 99%

Identification of critical residues of O-antigen-modifying O-acetyltransferase B (OacB) of Shigella flexneri

Rajput

Verma

2022

BMC Mol and Cell Biol

Self Cite

View full text Add to dashboard Cite

Background Shigellosis is an acute gastrointestinal disease caused primarily by the bacterium Shigella flexneri. Upon ingestion, S. flexneri initiates a serotype-specific immune response that targets the O-antigen of the pathogen’s lipopolysaccharide. O-antigen subunits are modified by the addition of chemical moieties, which give rise to new serotypes of S. flexneri. Nineteen different serotypes of S. flexneri have been recognized. A recently identified O-antigen-modifying enzyme, O-acetyltransferase B (OacB), which adds an acetyl residue at either position 3 or 4 of RhamnoseIII (3/4-O-acetylation) in serotypes 1a, 1b, 2a, 5a, 7a, Y, and 6 and position 6 of N- acetylglucosamine (6-O-acetylation) in serotypes 2a, 3a, Y and Yv of the O-antigen subunits. Critical residues in other proteins involved in O-antigen modifications such as glucosyltransferases (Gtrs) and acetyltransferase (Oac) of S. flexneri have been identified, whereas identification of important amino acids in OacB function is yet to be determined. Results Hydrophobicity analysis showed that OacB is a transmembrane protein with 11 transmembrane segments, 12 loops, and periplasmic N- and cytoplasmic C- termini. Bioinformatics analyses revealed that OacB contains acetyltransferase-3 domain and several conserved residues. Using site-directed mutagenesis, selected amino acids were mutated to alanine to elucidate their role in the mechanism of action of OacB. Seven amino acids R47, H58, F98, W71, R116, R119, and S146 were found critical for the OacB function. Conclusion In the absence of a three-dimensional structure of the serotype converting enzyme, O-acetyltransferase B (OacB), a clear role of important residues in the mechanism of action is precluded. Therefore, in this study, using site-directed mutagenesis, seven residues critical to the function of OacB were identified. The lack of agglutination of cell expressing mutant OacB in the presence of the antiserum indicated the functional role of the corresponding residues. Hence, this study provides significant information about key residues in OacB which might be involved in forming the catalytic sites of this O-antigen modifying enzyme of S. flexneri.

show abstract

New insight into transmembrane topology of Staphylococcus aureus histidine kinase AgrC

Wang

Quan

Xiong

et al. 2014

Biochimica et Biophysica Acta (BBA) - Biomembranes

View full text Add to dashboard Cite

Staphylococcus aureus accessory gene regulator (agr) locus controls the expression of virulence factors through a classical two-component signal transduction system that consists of a receptor histidine protein kinase AgrC and a cytoplasmic response regulator AgrA. An autoinducing peptide (AIP) encoded by agr locus activates AgrC, which transduces extracellular signals into the cytoplasm. Despite extensive investigations to identify AgrC-AIP interaction sites, precise signal recognition mechanisms remain unknown. This study aims to clarify the membrane topology of AgrC by applying the green fluorescent protein (GFP) fusion technique and the substituted cysteine accessibility method (SCAM). However, our findings were inconsistent with profile obtained previously by alkaline phosphatase. We report the topology of AgrC shows seven transmembrane segments, a periplasmic N-terminus, and a cytoplasmic C-terminus.

show abstract

Topological Investigation of Glucosyltransferase V in Shigella flexneri using the Substituted Cysteine Accessibility Method

Cited by 6 publications

References 38 publications

O-Antigen modifications providing antigenic diversity of Shigella flexneri and underlying genetic mechanisms

O-Antigen modifications providing antigenic diversity of Shigella flexneri and underlying genetic mechanisms

Identification of critical residues of O-antigen-modifying O-acetyltransferase B (OacB) of Shigella flexneri

New insight into transmembrane topology of Staphylococcus aureus histidine kinase AgrC

Contact Info

Product

Resources

About