Engineering Escherichia coli for increased Und-P availability leads to material improvements in glycan expression technology.

Background: Bacterial surface glycans are assembled by glycosyltransferases (GTs) that transfer sugar monomers to long-chained lipid carriers. Most bacteria employ the 55-carbon chain undecaprenyl phosphate (Und-P) to scaffold glycan assembly. The amount of Und-P available for glycan synthesis is thought to be limited by the rate of Und-P synthesis and by competition for Und-P between phosphoglycosyl transferases (PGTs) and GTs that prime glycan assembly (which we collectively refer to as PGT/GTs).

A genetic screen to identify factors affected by undecaprenyl phosphate recycling uncovers novel connections to morphogenesis in Escherichia coli.

Undecaprenyl phosphate (Und-P) is an essential lipid carrier that ferries cell wall intermediates across the cytoplasmic membrane in bacteria. Und-P is generated by dephosphorylating undecaprenyl pyrophosphate (Und-PP). In Escherichia coli, BacA, PgpB, YbjG, and LpxT dephosphorylate Und-PP and are conditionally essential.

Simultaneously inhibiting undecaprenyl phosphate production and peptidoglycan synthases promotes rapid lysis in Escherichia coli.

Peptidoglycan (PG) is a highly cross-linked polysaccharide that encases bacteria, resists the effects of turgor and confers cell shape. PG precursors are translocated across the cytoplasmic membrane by the lipid carrier undecaprenyl phosphate (Und-P) where they are incorporated into the PG superstructure. Previously, we found that one of our Escherichia coli laboratory strains (CS109) harbors a missense mutation in uppS, which encodes an enzymatically defective Und-P(P) synthase.

Pyruvate oxidase of Streptococcus pneumoniae contributes to pneumolysin release.

Background: Streptococcus pneumoniae is one of the leading causes of community acquired pneumonia and acute otitis media. Certain aspects of S. pneumoniae's virulence are dependent upon expression and release of the protein toxin pneumolysin (PLY) and upon the activity of the peroxide-producing enzyme, pyruvate oxidase (SpxB).