Bacterial polysaccharide synthesis and export

Woodward, L.; Naismith, James H.

doi:10.1016/j.sbi.2016.07.016

Cited by 29 publications

(22 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The bacterial capsule serves a variety of functions, including, but not limited to, protection from the immune response of the host ( 56 , 62 – 64 ). Capsule synthesis in K. pneumoniae is homologous to assembly of the Wzy-dependent assembly of group 1 capsules of E. coli ( 65 ). Following polymerization, the polysaccharide chains are transported across the outer membrane and are thought to be anchored to the surface via the Wzi lectin ( 66 , 67 ).…”

Section: Discussionmentioning

confidence: 99%

Identification of Two Regulators of Virulence That Are Conserved in Klebsiella pneumoniae Classical and Hypervirulent Strains

Palacios

Miner

Frederick

et al. 2018

mBio

View full text Add to dashboard Cite

Klebsiella pneumoniae is widely recognized as a pathogen with a propensity for acquiring antibiotic resistance. It is capable of causing a range of hospital-acquired infections (urinary tract infections [UTI], pneumonia, sepsis) and community-acquired invasive infections. The genetic heterogeneity of K. pneumoniae isolates complicates our ability to understand the virulence of K. pneumoniae. Characterization of virulence factors conserved between strains as well as strain-specific factors will improve our understanding of this important pathogen. The MarR family of regulatory proteins is widely distributed in bacteria and regulates cellular processes such as antibiotic resistance and the expression of virulence factors. Klebsiella encodes numerous MarR-like proteins, and they likely contribute to the ability of K. pneumoniae to respond to and survive under a wide variety of environmental conditions, including those present in the human body. We tested loss-of-function mutations in all the marR homologues in a murine pneumonia model and found that two (kvrA and kvrB) significantly impacted the virulence of K1 and K2 capsule type hypervirulent (hv) strains and that kvrA affected the virulence of a sequence type 258 (ST258) classical strain. In the hv strains, kvrA and kvrB mutants displayed phenotypes associated with reduced capsule production, mucoviscosity, and transcription from galF and manC promoters that drive expression of capsule synthesis genes. In contrast, kvrA and kvrB mutants in the ST258 strain had no effect on capsule gene expression or capsule-related phenotypes. Thus, KvrA and KvrB affect virulence in classical and hv strains but the effect on virulence may not be exclusively due to effects on capsule production.

show abstract

Section: Discussionmentioning

confidence: 99%

Identification of Two Regulators of Virulence That Are Conserved in Klebsiella pneumoniae Classical and Hypervirulent Strains

Palacios

Miner

Frederick

et al. 2018

mBio

View full text Add to dashboard Cite

show abstract

“…In the biosynthesis of the E. coli O9a antigen, glycan polymerization is catalyzed by the mannosyltransferase WbdA, and the length of the growing glycan chain is controlled by the C-terminal domain of the associated WbdD protein, which adopts a coiled-coil folding and acts as a molecular ruler 40 . In the biosynthesis of bacterial lipopolysaccharide, glycan repeats are polymerized by the integral membrane protein Wzy, and the length of the polymer is regulated by Wzz, using an unknown mechanism 41 . In contrast, PglH is not an integral transmembrane protein and does not require an additional partner to perform the glycan counting.…”

Section: Discussionmentioning

confidence: 99%

Structural basis of the molecular ruler mechanism of a bacterial glycosyltransferase

et al. 2018

View full text Add to dashboard Cite

The membrane-associated, processive and retaining glycosyltransferase PglH from Campylobacter jejuni is part of the biosynthetic pathway of the lipid-linked oligosaccharide (LLO) that serves as the glycan donor in bacterial protein N-glycosylation. Using an unknown counting mechanism, PglH catalyzes the transfer of exactly three α1,4 N-acetylgalactosamine (GalNAc) units to the growing LLO precursor, GalNAc-α1,4-GalNAc-α1,3-Bac-α1-PP-undecaprenyl. Here, we present crystal structures of PglH in three distinct states, including a binary complex with UDP-GalNAc and two ternary complexes containing a chemo-enzymatically generated LLO analog and either UDP or synthetic, nonhydrolyzable UDP-CH2-GalNAc. PglH contains an amphipathic helix (“ruler helix”) that has a dual role of facilitating membrane attachment and glycan counting. The ruler helix contains three positively charged side chains that can bind the pyrophosphate group of the LLO substrate and thus limit the addition of GalNAc units to three. These results, combined with molecular dynamics simulations, provide the mechanism of glycan counting by PglH.

show abstract

“…Several genes involved in polysaccharide biosynthesis were upregulated, which is essential for building the outer lea et of the outer membrane surface (32). Genes in the retrograde phospholipid tra cking pathway mlaABCD were signi cantly downregulated.…”

Section: Adaptations For Inner Membrane Biogenesis In C41(de3) and C4mentioning

confidence: 99%

Deciphering the transcriptional changes in Escherichia coli strains C41(DE3) and C43(DE3) that makes them a superior choice for membrane protein production.

Webb

Lithgow

2020

Preprint

View full text Add to dashboard Cite

Background: The production of membrane proteins for functional and structural protein analysis remains a bottleneck in the continuing quest for understanding biological systems. For recombinant membrane proteins, the Walker strains C41(DE3) and C43(DE3) are a valuable tool because they are capable of producing levels of functional protein that would otherwise be toxic to the cell. At the genome level, amongst only a handful of genetic changes, mutations in the lacUV5 promoter region upstream from the bacteriophage T7 RNA polymerase gene distinguish these strains from BL21(DE3) but do not inform on how the strains have adapted for superior production of recombinant membrane proteins. Results: Comparative transcriptomic analyses revealed a moderate change in gene expression in C41(DE3) and C43(DE3) compared to their parent strain BL21(DE3) under standard growth conditions. However, under the conditions used for membrane protein production (with plasmid carriage and addition of IPTG), the differential response of C41(DE3) and C43(DE3) compared to their parent strain BL21(DE3) was striking. Over 2000 genes were differentially expressed in C41(DE3) with a two-fold change and false discover rate < 0.01 and 1700 genes differentially expressed in C43(DE3) compared to their parent strain BL21(DE3). Conclusion: These results illuminate the cellular adaptations occurring in the Walker strains to alleviate the toxic effects that can occur during membrane protein production, whilst providing changes in metabolism pathways required for membrane protein biogenesis. The BL21(DE3) derivatives strains C41(DE3) and C43(DE3), are adept to the process of membrane biogenesis in E. coli, making them superior to their parent strain for the production of membrane proteins and potentially other toxic proteins.

show abstract

Bacterial polysaccharide synthesis and export

Cited by 29 publications

References 43 publications

Identification of Two Regulators of Virulence That Are Conserved in Klebsiella pneumoniae Classical and Hypervirulent Strains

Identification of Two Regulators of Virulence That Are Conserved in Klebsiella pneumoniae Classical and Hypervirulent Strains

Structural basis of the molecular ruler mechanism of a bacterial glycosyltransferase

Deciphering the transcriptional changes in Escherichia coli strains C41(DE3) and C43(DE3) that makes them a superior choice for membrane protein production.

Contact Info

Product

Resources

About