Abstract
Bacterial capsules have critical roles in host-pathogen interactions. They provide a protective envelope against host recognition, leading to immune evasion and bacterial survival. Here we define the capsule biosynthesis pathway of Haemophilus influenzae serotype b (Hib), a Gram-negative bacterium that causes severe infections in infants and children. Reconstitution of this pathway enabled the fermentation-free production of Hib vaccine antigens starting from widely available precursors and detailed characterization of the enzymatic machinery. The X-ray crystal structure of the capsule polymerase Bcs3 reveals a multi-enzyme machine adopting a basket-like shape that creates a protected environment for the synthesis of the complex Hib polymer. This architecture is commonly exploited for surface glycan synthesis by both Gram-negative and Gram-positive pathogens. Supported by biochemical studies and comprehensive 2D nuclear magnetic resonance, our data explain how the ribofuranosyltransferase CriT, the phosphatase CrpP, the ribitol-phosphate transferase CroT and a polymer-binding domain function as a unique multi-enzyme assembly.
Original language | English |
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Pages (from-to) | 865-877 |
Number of pages | 13 |
Journal | Nature Chemical Biology |
Volume | 19 |
Issue number | 7 |
DOIs | |
Publication status | Published - 5 Jun 2023 |
Bibliographical note
Publisher Copyright:© 2023, The Author(s).
© 2023. The Author(s).
Keywords
- Haemophilus influenzae
- Capsule
- cell envelope
- teichoic acid
- vaccine development
- enzymatic synthesis
- ribose
- PRPP
- enzyme specificity
- bacterial pathogenesis
- nuclear magnetic resonance (NMR)
- X-ray crystallography
- HAD-like phosphatase
- polysaccharide
- Gram-Negative Bacteria
- Humans
- Infant
- Bacterial Capsules/metabolism
- Haemophilus Infections/microbiology
- Haemophilus Vaccines/metabolism
- Haemophilus influenzae type b
- Child
Fields of Science and Technology Classification 2012
- 303 Health Sciences
- 304 Medical Biotechnology
- 106 Biology