scholarly journals Genomic diversity and organization of complex polysaccharide biosynthesis clusters in the genus Dickeya

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245727
Author(s):  
Manish Ranjan ◽  
Devanshi Khokhani ◽  
Sanjeeva Nayaka ◽  
Suchi Srivastava ◽  
Zachary P. Keyser ◽  
...  
Keyword(s):  
Gene Clusters ◽  
Genomic Diversity ◽  
Extracellular Polysaccharides ◽  
Common Antigen ◽  
Coding Region ◽  
O Antigen ◽  
Enterobacterial Common Antigen ◽  
Group 4 ◽  
Group I ◽  
Lipopolysaccharide Biosynthesis

The pectinolytic genus Dickeya (formerly Erwinia chrysanthemi) comprises numerous pathogenic species which cause diseases in various crops and ornamental plants across the globe. Their pathogenicity is governed by complex multi-factorial processes of adaptive virulence gene regulation. Extracellular polysaccharides and lipopolysaccharides present on bacterial envelope surface play a significant role in the virulence of phytopathogenic bacteria. However, very little is known about the genomic location, diversity, and organization of the polysaccharide and lipopolysaccharide biosynthetic gene clusters in Dickeya. In the present study, we report the diversity and structural organization of the group 4 capsule (G4C)/O-antigen capsule, putative O-antigen lipopolysaccharide, enterobacterial common antigen, and core lipopolysaccharide biosynthesis clusters from 54 Dickeya strains. The presence of these clusters suggests that Dickeya has both capsule and lipopolysaccharide carrying O-antigen to their external surface. These gene clusters are key regulatory components in the composition and structure of the outer surface of Dickeya. The O-antigen capsule/group 4 capsule (G4C) coding region shows a variation in gene content and organization. Based on nucleotide sequence homology in these Dickeya strains, two distinct groups, G4C group I and G4C group II, exist. However, comparatively less variation is observed in the putative O-antigen lipopolysaccharide cluster in Dickeya spp. except for in Dickeya zeae. Also, enterobacterial common antigen and core lipopolysaccharide biosynthesis clusters are present mostly as conserved genomic regions. The variation in the O-antigen capsule and putative O-antigen lipopolysaccharide coding region in relation to their phylogeny suggests a role of multiple horizontal gene transfer (HGT) events. These multiple HGT processes might have been manifested into the current heterogeneity of O-antigen capsules and O-antigen lipopolysaccharides in Dickeya strains during its evolution.

Deletion of the Escherichia coli O14:K7 O antigen gene cluster

2004 ◽  
Vol 50 (4) ◽  
pp. 299-302 ◽  
Author(s):  
Slade O Jensen ◽  
Peter R Reeves
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Common Antigen ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Enterobacterial Common Antigen ◽  
Colanic Acid ◽  
Rough Strain

Escherichia coli O14:K7 is a rough strain, lacking a typical O antigen, in which the enterobacterial common antigen is attached to the lipopolysaccharide core. The rough phenotype was previously mapped to the O antigen gene cluster; however, the nature of the nonfunctional locus was not defined. In this study, we have shown that the O antigen gene cluster of an O14:K7 type strain (Su4411/41) was most likely deleted via homologous recombination between the GDP–mannose pathway genes (manB and manC) of the colanic acid and O antigen gene clusters. A similar recombination event has previously been inferred for the deletion of E. coli Sonnei chromosomal O antigen genes. Therefore, recombination between the GDP–mannose pathway genes provides a convenient mechanism for the deletion of O antigen genes, which may occur if the typical O antigen becomes redundant.Key words: colanic acid, enterobacterial common antigen, GDP–mannose pathway, O14:K7, O antigen.

scholarly journals Functional Characterization and Membrane Topology of Escherichia coli WecA, a Sugar-Phosphate Transferase Initiating the Biosynthesis of Enterobacterial Common Antigen and O-Antigen Lipopolysaccharide

2007 ◽  
Vol 189 (7) ◽  
pp. 2618-2628 ◽  
Author(s):  
Jason Lehrer ◽  
Karen A. Vigeant ◽  
Laura D. Tatar ◽  
Miguel A. Valvano
Keyword(s):  
Fluorescent Protein ◽  
Topological Analysis ◽  
Functional Characterization ◽  
Membrane Topology ◽  
Common Antigen ◽  
Topological Map ◽  
O Antigen ◽  
Substituted Cysteine Accessibility ◽  
Enterobacterial Common Antigen

ABSTRACT WecA is an integral membrane protein that initiates the biosynthesis of enterobacterial common antigen and O-antigen lipopolysaccharide (LPS) by catalyzing the transfer of N-acetylglucosamine (GlcNAc)-1-phosphate onto undecaprenyl phosphate (Und-P) to form Und-P-P-GlcNAc. WecA belongs to a large family of eukaryotic and prokaryotic prenyl sugar transferases. Conserved aspartic acids in putative cytoplasmic loops 2 (Asp90 and Asp91) and 3 (Asp156 and Asp159) were targeted for replacement mutagenesis with either glutamic acid or asparagine. We examined the ability of each mutant protein to complement O-antigen LPS synthesis in a wecA-deficient strain and also determined the steady-state kinetic parameters of the mutant proteins in an in vitro transfer assay. Apparent Km and V max values for UDP-GlcNAc, Mg2+, and Mn2+ suggest that Asp156 is required for catalysis, while Asp91 appears to interact preferentially with Mg2+, possibly playing a role in orienting the substrates. Topological analysis using the substituted cysteine accessibility method demonstrated the cytosolic location of Asp90, Asp91, and Asp156 and provided a more refined overall topological map of WecA. Also, we show that cells expressing a WecA derivative C terminally fused with the green fluorescent protein exhibited a punctate distribution of fluorescence on the bacterial surface, suggesting that WecA localizes to discrete regions in the bacterial plasma membrane.

scholarly journals Structure of the O-antigen of Salmonella O66 and the genetic basis for similarity and differences between the closely related O-antigens of Escherichia coli O166 and Salmonella O66

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1642-1649 ◽  
Author(s):  
Bin Liu ◽  
Andrei V. Perepelov ◽  
Dan Li ◽  
Sof'ya N. Senchenkova ◽  
Yanfang Han ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Coding Region ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
New Genes ◽  
O Antigens ◽  
Antigen Structure

O-antigen is a component of the outer membrane of Gram-negative bacteria and is one of the most variable cell surface constituents, leading to major antigenic variability. The O-antigen forms the basis for bacterial serotyping. In this study, the O-antigen structure of Salmonella O66 was established, which differs from the known O-antigen structure of Escherichia coli O166 only in one linkage (most likely the linkage between the O-units) and O-acetylation. The O-antigen gene clusters of Salmonella O66 and E. coli O166 were found to have similar organizations, the only exception being that in Salmonella O66, the wzy gene is replaced by a non-coding region. The function of the wzy gene in E. coli O166 was confirmed by the construction and analysis of deletion and trans-complementation mutants. It is proposed that a functional wzy gene located outside the O-antigen gene cluster is involved in Salmonella O66 O-antigen biosynthesis, as has been reported previously in Salmonella serogroups A, B and D1. The sequence identity for the corresponding genes between the O-antigen gene clusters of Salmonella O66 and E. coli O166 ranges from 64 to 70 %, indicating that they may originate from a common ancestor. It is likely that after the species divergence, Salmonella O66 got its specific O-antigen form by inactivation of the wzy gene located in the O-antigen gene cluster and acquisition of two new genes (a wzy gene and a prophage gene for O-acetyl modification) both residing outside the O-antigen gene cluster.

scholarly journals Polysaccharide co-polymerase WzzB/WzzE chimeras reveal transmembrane 2 region of WzzB is important for interaction with WzyB

2020 ◽  
Author(s):  
Vincenzo Leo ◽  
Elizabeth Tran ◽  
Renato Morona
Keyword(s):  
Cross Talk ◽  
Protein Interactions ◽  
Biological Activities ◽  
Critical Role ◽  
Common Antigen ◽  
Modal Length ◽  
O Antigen ◽  
Enterobacterial Common Antigen ◽  
First Time ◽  
Dependent Pathway

The ability of bacteria to synthesise complex polysaccharide chains at a controlled number of repeating units has wide implications for a range of biological activities that include: symbiosis, biofilm formation and immune system avoidance. Complex polysaccharide chains such as the O antigen (Oag) component of lipopolysaccharide and the enterobacterial common antigen (ECA) are synthesised by the most common polysaccharide synthesis pathway used in bacteria, known as the Wzy-dependent pathway. The Oag and ECA are polymerized into chains via the inner membrane proteins WzyB and WzyE, respectively, while the respective co-polymerases WzzB and WzzE modulate the number of repeat units in the chains or “the modal length” of the polysaccharide via a hypothesised interaction. Our data shows for the first time “cross-talk” between Oag and ECA synthesis in that WzzE is able to partially regulate Oag modal length via a potential interaction with WzyB. To investigate this, one or both of the transmembrane regions (TM1 and TM2) of WzzE and WzzB were swapped creating six chimera proteins. Several chimeric proteins showed significant increases Oag modal length control, while others reduced control. Additionally, co-purification experiments show an interaction between WzyB and WzzB for the first time without the use of a chemical cross-linker, and a novel interaction between WzyB and WzzE. These results suggest the TM2 region of Wzz proteins plays a critical role in Oag and ECA modal length control, presumably via the interaction with respective Wzy proteins, thus providing insight into the complex mechanism underlying the control of polysaccharide biosynthesis. Importance Bacteria synthesise complex polysaccharide chains at a controlled number of repeating units, this has wide implications for a range of bacterial activities involved in virulence. Examples of complex polysaccharide chains include, the O antigen (Oag) component of lipopolysaccharide and the enterobacterial common antigen (ECA), both of these examples are predominantly synthesised by their own independent Wzy-dependent pathway. Our data show for the first time “cross-talk” between Oag and ECA synthesis and identifies novel physical protein-protein interactions between proteins in these systems. These findings further the understanding of how the system functions to control polysaccharide chain length which has great implications for novel biotechnologies and/or the combat of bacterial diseases.

scholarly journals Relationship between O-antigen subtypes, bacterial surface structures and O-antigen gene clusters in Escherichia coli O123 strains carrying genes for Shiga toxins and intimin

2007 ◽  
Vol 56 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Lothar Beutin ◽  
Quan Wang ◽  
Dieter Naumann ◽  
Weiqing Han ◽  
Gladys Krause ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid Level ◽  
Gene Clusters ◽  
Surface Structures ◽  
Nucleotide Sequence Analysis ◽  
E Coli ◽  
Antigen Gene ◽  
O Antigen ◽  
Group I ◽  
Group Ii

Escherichia coli O123 strains express a broad spectrum of phenotypes, H serotypes and virulence markers and are able to colonize and to cause disease in different hosts including humans. In this study, two subtypes of E. coli O123 antigen (group I and group II) have been identified based on their cross-reactions with other E. coli O antigens. Investigation of the relationship between O123 group I and group II strains by O serotyping and Fourier transform infrared spectroscopy of whole bacteria revealed surface structural differences between these two groups of E. coli O123 strains. Nucleotide sequence analysis of the O-antigen gene clusters of two E. coli O123 strains representing O123 group I and group II revealed no change at the amino acid level. These findings indicate that the differences in the surface structures of group I and group II strains are not related to genetic heterogeneity in their O-antigen gene clusters. A PCR assay based on O123 antigen-specific wzx and wzy genes was developed and found to be suitable for reliable detection of all subtypes of E. coli O123 strains, which bears an advantage over traditional serological detection.

scholarly journals Genome Reduction and Secondary Metabolism of the Marine Sponge-Associated Cyanobacterium Leptothoe

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 298
Author(s):  
Despoina Konstantinou ◽  
Rafael V. Popin ◽  
David P. Fewer ◽  
Kaarina Sivonen ◽  
Spyros Gkelis
Keyword(s):  
Natural Products ◽  
Microbial Communities ◽  
Genomic Analysis ◽  
Gene Clusters ◽  
Marine Sponges ◽  
Genome Reduction ◽  
Extracellular Polysaccharides ◽  
Comparative Genomic ◽  
Symbiotic Relationships ◽  
Genes Encoding

Sponges form symbiotic relationships with diverse and abundant microbial communities. Cyanobacteria are among the most important members of the microbial communities that are associated with sponges. Here, we performed a genus-wide comparative genomic analysis of the newly described marine benthic cyanobacterial genus Leptothoe (Synechococcales). We obtained draft genomes from Le. kymatousa TAU-MAC 1615 and Le. spongobia TAU-MAC 1115, isolated from marine sponges. We identified five additional Leptothoe genomes, host-associated or free-living, using a phylogenomic approach, and the comparison of all genomes showed that the sponge-associated strains display features of a symbiotic lifestyle. Le. kymatousa and Le. spongobia have undergone genome reduction; they harbored considerably fewer genes encoding for (i) cofactors, vitamins, prosthetic groups, pigments, proteins, and amino acid biosynthesis; (ii) DNA repair; (iii) antioxidant enzymes; and (iv) biosynthesis of capsular and extracellular polysaccharides. They have also lost several genes related to chemotaxis and motility. Eukaryotic-like proteins, such as ankyrin repeats, playing important roles in sponge-symbiont interactions, were identified in sponge-associated Leptothoe genomes. The sponge-associated Leptothoe stains harbored biosynthetic gene clusters encoding novel natural products despite genome reduction. Comparisons of the biosynthetic capacities of Leptothoe with chemically rich cyanobacteria revealed that Leptothoe is another promising marine cyanobacterium for the biosynthesis of novel natural products.

scholarly journals A New Look at the Enterobacterial Common Antigen Forms Obtained during Rough Lipopolysaccharides Purification

2021 ◽  
Vol 22 (2) ◽  
pp. 701
Author(s):  
Tomasz K Gozdziewicz ◽  
Anna Maciejewska ◽  
Alona Tsybulska ◽  
Czeslaw Lugowski ◽  
Jolanta Lukasiewicz
Keyword(s):  
Current Knowledge ◽  
Membrane Integrity ◽  
Gel Filtration ◽  
Common Antigen ◽  
Mild Acid Hydrolysis ◽  
Enterobacterial Common Antigen ◽  
Lipopolysaccharide Endotoxin ◽  
Lipid Moiety ◽  
Detailed Composition ◽  
Mild Acid

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fucp4NAc-(1→4)-β-D-ManpNAcA-(1→4)-α-D-GlcpNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECAPG) or lipopolysaccharide − endotoxin (ECALPS), and cyclic form (ECACYC). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria. A supernatant obtained after LPS ultracentrifugation was reported as a source for ECA isolation, but it has never been assessed for detailed composition besides ECACYC. We used mild acid hydrolysis and gel filtration, or zwitterionic-hydrophilic interaction liquid (ZIC®HILIC) chromatography combined with mass spectrometry for purification, fractionation, and structural analysis of rough Shigella sonnei and Escherichia coli R1 and K12 crude LPS preparations. Presented work is the first report concerning complex characteristic of all ECA forms present in LPS-derived supernatants. We demonstrated high heterogeneity of the supernatant-derived ECA that contaminate LPS purified by ultracentrifugation. Not only previously reported O-acetylated tetrameric, pentameric, and hexameric ECACYC have been identified, but also devoid of lipid moiety linear ECA built from 7 to 11 repeating units. Described results were common for all selected strains. The origin of linear ECA is discussed against the current knowledge about ECAPG and ECALPS.

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