PNNL

Abstract

Acetylation is a dynamic post-translational modification of proteins which, like phosphorylation, regulates a variety of cellular functions. Unlike phosphorylation, where signaling pathways have been studied for decades1,2, the extent of the regulatory nature of acetylation has not been as fully explored. Global acetylome surveys have frequently identified an enrichment of glycolysis and TCA proteins3,4; however, the role or mechanism of action of this modification has yet to be fully elucidated. Here we show that acetylated lysines are present in structurally defined substrate/cofactor binding sites of eleven glycolytic and TCA enzymes. Acetylation data was generated for 48 phylogenetically diverse bacteria; acetylated lysines are invariant across evolution and acetylated in multiple organisms within the phyloproteomics dataset, suggesting this is an ancient regulatory mechanism present in all bacteria. We identified an additional 5 glycolytic and TCA enzymes that have invariant and acetylated lysines but are functionally unannotated, some of these are adjacent to substrate binding residues. In total, >60% of all TCA and glycolytic enzymes contained invariant lysines that were acetylated. Lysine acetylation in binding sites disrupts binding by removing the residue’s charge and potential for hydrogen bonding, and also by occluding the substrate binding pocket and possibly changing the binding site geometry. Our data suggests that, unlike phosphorylation whose biological function is frequently relaying signals, acetylation may play a role in regulation by switching off enzyme activity.