Regulation of the pyrimidine biosynthetic pathway by lysine acetylation of E. coliOPRTase

Abstract

The de novo pyrimidine biosynthesis pathway is an important route due to the relevance of its products, its implications in health and its conservation among organisms. Here, we investigated the regulation by lysine acetylation of this pathway. To this aim, intracellular and extracellular metabolites of the route were quantified, revealing a possible blockage of the pathway by acetylation of the OPRTase enzyme (orotate phosphoribosyltransferase). Chemical acetylation of OPRTase by acetyl‐P involved a decrease in enzymatic activity. To test the effect of acetylation in this enzyme, K26 and K103 residues were selected to generate site‐specific acetylated proteins. Several differences were observed in kinetic parameters, emphasizing that the kcat of these mutants showed a strong decrease of 300 and 150‐fold for OPRTase‐103AcK and 19 and 6.3‐fold for OPRTase‐26AcK, for forward and reverse reactions. In vivo studies suggested acetylation of this enzyme by a nonenzymatic acetyl‐P‐dependent mechanism and a reversion of this process by the CobB deacetylase. A complementation assay of a deficient strain in the pyrE gene with OPRTase‐26AcK and OPRTase‐103AcK was performed, and curli formation, stoichiometric parameters and orotate excretion were measured. Complementation with acetylated enzymes entailed a profile very similar to that of the ∆pyrE strain, especially in the case of complementation with OPRTase‐103AcK. These results suggest regulation of the de novo pyrimidine biosynthesis pathway by lysine acetylation of OPRTase in Escherichia coli. This finding is of great relevance due to the essential role of this route and the OPRTase enzyme as a target for antimicrobial, antiviral and cancer treatments.

Mapping protein-metabolite interactions inE. coliby integrating chromatographic techniques and co-fractionation mass spectrometry

“…In our experiment, treatment of lumichrome resulted in the inhibitory effect on Congo-red binding in a concentration-dependent manner ( Figure 4j ). This observation is consistent with the reduced bacterial motility and biofilm formation in Δ pyrE mutant strain of Pseudomonas aeruginosa (PA01) (Niazy et al , 2022) and E. coli (Lozano-Terol et al , 2023). Additionally, inhibition of biofilm formation in E. coli was observed with a decrease in PyrE activity due to acetylation at lysine 26 and 103 position (Lozano-Terol et al , 2023).…”