Oacetyltransferase

Oacetyltransferase refers to enzymes that catalyze the transfer of an acetyl group from acetyl-CoA to an oxygen-containing acceptor, producing an O-acetylated product and CoA. This broad class encompasses enzymes from bacteria, plants, and fungi and includes several structural families, among them members of the GNAT (Gcn5-related N-acetyltransferase) superfamily that can transfer acetyl groups to hydroxyl or other oxygen-bearing substrates.

The substrates and roles of o-acetyltransferases are diverse. Many modify carbohydrates or other small molecules by attaching an acetyl group to a hydroxyl, forming an O-acetyl ether. In bacteria, a well-studied subgroup O-acetylates peptidoglycan; for example, O-acetylation of N-acetylmuramic acid at the O-6 position can alter cell wall properties and increase resistance to lysozyme. A notable enzyme in this pathway is OatA, found in several Gram-positive organisms, which uses acetyl-CoA to acetylate MurNAc residues in peptidoglycan and thereby influences virulence and immune evasion.

Other o-acetyltransferases act on different carbohydrate intermediates or secondary metabolites, reflecting functional diversity beyond cell wall modification. Mechanistically, many operate by directly transferring the acetyl group from acetyl-CoA to the oxygen atom of the substrate; some families may involve transient enzyme-bound acetyl intermediates.

Oacetyltransferases are of interest in science and medicine because their activity can affect cell wall integrity, enzyme resistance, and pathogenicity, making them potential targets for antimicrobial strategies. The term also serves to distinguish these enzymes from acyltransferases that transfer longer or different acyl groups to various substrates.