Download MendeleyThe mechanism of peptidoglycan O-acetylation in Gram-negative bacteria typifies bacterial MBOAT-SGNH acyltransferases.
Anderson, A.C., Schultz, B.J., Snow, E.D., Brott, A.S., Stangherlin, S., Malloch, T., London, J.R., Walker, S., Clarke, A.J.(2025) J Biological Chem 301: 108531-108531
- PubMed: 40280421
- DOI: https://doi.org/10.1016/j.jbc.2025.108531
- Primary Citation of Related Structures:
8TLB - PubMed Abstract:
Bacterial cell envelope polymers are commonly modified with acyl groups that provide fitness advantages. Many polymer acylation pathways involve pairs of membrane-bound O-acyltransferase (MBOAT) and SGNH family proteins. As an example, the MBOAT protein PatA and the SGNH protein PatB are required in Gram-negative bacteria for peptidoglycan O-acetylation. The mechanism for how MBOAT-SGNH transferases move acyl groups from acyl-CoA donors made in the cytoplasm to extracellular polymers is unclear. Using the peptidoglycan O-acetyltransferase proteins PatAB, we explore the mechanism of MBOAT-SGNH pairs. We find that the MBOAT protein PatA catalyzes auto-acetylation of an invariant Tyr residue in its conserved C-terminal hexapeptide motif. We also show that PatB can use a synthetic hexapeptide containing an acetylated tyrosine to donate an acetyl group to a peptidoglycan mimetic. Finally, we report the structure of PatB, finding that it has structural features that shape its activity as an O-acetyltransferase and distinguish it from other SGNH esterases and hydrolases. Taken together, our results support a model for peptidoglycan acylation in which a tyrosine-containing peptide at the MBOAT's C-terminus shuttles an acyl group from the MBOAT active site to the SGNH active site, where it is transferred to peptidoglycan. This model likely applies to other systems containing MBOAT-SGNH pairs, such as those that O-acetylate alginate, cellulose, and secondary cell wall polysaccharides.
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
Organizational Affiliation:
