capsule

Edge evidence

• capsular polysaccharide assembly produces capsular polysaccharide biolink:produces

  Capsule biosynthesis synthesizes and exports the high-MW capsular polysaccharide.

  • DOI:10.1146/annurev.biochem.75.103004.142545 Whitfield reviews biosynthesis, export, and surface assembly of the capsular polysaccharide polymer.
• capsular polysaccharide assembly enables capsule RO:0002327

  Surface assembly of capsule polymers realizes the capsulated phenotype.

  • DOI:10.1146/annurev.biochem.75.103004.142545 Whitfield reviews biosynthesis and assembly of capsular polysaccharides.
• capsule contributes to host immune evasion RO:0002326

  The capsule masks surface antigens and reduces phagocytic uptake.

  • DOI:10.1146/annurev.micro.50.1.285 Roberts frames capsular polysaccharide as an immune-evasion and adhesion structure.
• Wzx flippase flips lipid-linked capsule repeat unit

  Wzx flippase turns the completed lipid-linked repeat unit outward across the inner membrane.

  • DOI:10.1038/s41522-024-00497-6 "the complete repeat unit is turned outward by the Wzx flip enzyme"; general Wzx/Wzy capsule biosynthesis, not taxon-specific.
• Wzy polymerase polymerizes capsular polysaccharide

  Wzy polymerase attaches the growing chain to new repeat units, building the capsular polysaccharide.

  • DOI:10.1038/s41522-024-00497-6 "the Wzy polymerase attaches the growing polymer chain to the newly formed repeat unit"; general Wzx/Wzy pathway.
• Wzb phosphatase cycle required for Wzc-regulated capsule assembly

  The Wzb-catalyzed phosphorylation cycle of Wzc is a crucial step for capsule assembly.

  • DOI:10.1038/s41522-024-00497-6 "The phosphorylation cycle of Wzc, catalyzed by Wzb, is a crucial step."; general capsule biosynthesis.
• Wza outer-membrane export protein exports capsular polysaccharide METPO:2000209

  Wza translocates the assembled capsule polymer across the outer membrane.

  • DOI:10.1038/s41522-024-00497-6 "The polymer translocates across the outer membrane via Wza"; Wzx/Wzy-dependent pathway, broad mechanistic statement.
• KpsMT ABC transporter exports capsular polysaccharide METPO:2000209

  The KpsMT ABC transporter exports capsule polysaccharide chains across the inner membrane in the ABC-dependent pathway.

  • DOI:10.1038/s41522-024-00497-6 "the ABC transporter (KpsMT) plays a pivotal role in exporting these chains"; general ABC-dependent capsule export.