Staphylococcus aureus wall teichoic acid (WTA)

The Staphylococcus aureus wall teichoic acid (WTA) is an anionic glycopolymer unique to Gram-positive bacteria, consisting of polyribitol phosphate (polyRboP) chains of 40–60 repeats attached via a disaccharide linkage to the C6 hydroxyl of N-acetylmuramic acid residues in peptidoglycan. These polymers are decorated with N-acetylglucosamine (GlcNAc) sugars by enzymes like TarM, a glycosyltransferase that catalyzes GlcNAc transfer to ribitol units. WTA contributes to cell wall integrity, forming a multilayered envelope around peptidoglycan that is 20–30 nm thick with high cross-linking (~90%). Biologically, WTA modulates host immunity by influencing antibody responses, facilitates phage binding and genetic exchange, enhances virulence, and promotes antibiotic resistance, including in methicillin-resistant S. aureus strains. Structurally, TarM adopts a GT-B fold with a trimerization domain, enabling glycosylation via an SNi-like mechanism involving UDP-GlcNAc donor and polyRboP acceptor. Despite its pathological roles, WTA is not directly targeted by approved therapeutics, though its modification enzymes like TarM are studied for potential intervention in S. aureus infections. Variations in WTA composition occur across strains, impacting immune evasion and pathogenesis.

Other names

polyribitol phosphate (polyRboP)ribitol-type teichoic acid