Identification of lead compounds targeting the dTDP-L-rhamnose biosynthesis pathway using Streptococcus pyogenes

van der Beek, S. L.; Zorzoli, A.; Canak, E.; Chapman, R. N.; Meyer, B. H.; Boons, G.-J. P. H.; Dorfmueller, H. C.; van Sorge, N. M.

doi:10.1101/312157

bioRxiv · 10.1101/312157

Identification of lead compounds targeting the dTDP-L-rhamnose biosynthesis pathway using Streptococcus pyogenes

van der Beek, S. L.·Zorzoli, A.·Canak, E.·Chapman, R. N.·Meyer, B. H.·Boons, G.-J. P. H.·Dorfmueller, H. C.·van Sorge, N. M.

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Abstract

Biosynthesis of the nucleotide sugar precursor dTDP-L-rhamnose is critical for the viability and virulence of many human pathogenic bacteria, including Streptococcus pyogenes (Group A Streptococcus; GAS) and Streptococcus mutans. Those pathogens require dTDP-L-rhamnose for the production of structurally similar rhamnose polysaccharides in their cell wall. Via heterologous expression in S. mutans, we confirm that GAS RmlB and RmlC are critical for dTDP-L-rhamnose biosynthesis through their action as dTDP-glucose-4,6-dehydratase and dTDP-4-keto-6-deoxyglucose-3,5-epimerase enzymes, respectively. Complementation with GAS RmlB and RmlC containing specific point mutations corroborated the conservation of previous identified catalytic residues in these enzymes. Bio-layer interferometry was used to identify and confirm inhibitory lead compounds that bind to GAS dTDP-rhamnose biosynthesis enzymes RmlB, RmlC and GacA. One of the identified compounds, Ri03, inhibited growth of GAS as well as several other rhamnose-dependent streptococcal pathogens with an MIC50 of 120-410 M. We therefore conclude that inhibition of dTDP-L-rhamnose biosynthesis such as Ri03 affect streptococcal viability and can serve as a lead compound for the development of a new class of antibiotics that targets dTDP-rhamnose biosynthesis in pathogenic bacteria.

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van der Beek, S. L., Zorzoli, A., Canak, E., Chapman, R. N., Meyer, B. H., Boons, G.-J. P. H., Dorfmueller, H. C., van Sorge, N. M.. 2018-05-11. Identification of lead compounds targeting the dTDP-L-rhamnose biosynthesis pathway using Streptococcus pyogenes. https://doi.org/10.1101/312157

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