Late-stage polyribitol phosphate wall teichoic acid biosynthesis in Staphylococcus aureus

Area of Science:

• Microbiology
• Biochemistry
• Cell Biology

Background:

• Wall teichoic acids (WTAs) are crucial for Staphylococcus aureus cell envelope integrity and virulence.
• The precise biosynthetic pathway for S. aureus WTA has remained largely unelucidated, with prior research assuming similarities to Bacillus subtilis pathways.

Purpose of the Study:

• To elucidate the late-stage enzymatic pathway for the predominant polyribitol phosphate (PRP) WTA in Staphylococcus aureus.
• To identify and characterize novel WTA species and their regulatory mechanisms in S. aureus.

Main Methods:

• High-resolution polyacrylamide gel electrophoresis was employed to analyze WTA from gene deletion mutants.
• Complementation studies were performed to assess enzyme function in WTA synthesis.

Main Results:

• A revised pathway for ribitol phosphate-utilizing enzymes was proposed, with TarL identified as a bifunctional enzyme catalyzing both priming and polymerization.
• A second, distinct WTA, designated K-WTA, was identified, synthesized by TarK.
• K-WTA biosynthesis was found to be repressed by the accessory gene regulator (agr) system in S. aureus NCTC8325.

Conclusions:

• The study refines our understanding of S. aureus WTA biosynthesis, highlighting the bifunctional nature of TarL and TarK.
• The discovery of K-WTA and its regulation by the agr system provides new insights into cell envelope remodeling and its impact on S. aureus pathogenesis and adhesion.