Meeting Abstract

P1.88  Tuesday, Jan. 4  Stabilization of Escherichia coli Methionine Cycle Upon Simulated Insertion of Arabidopsis Thaliana MMT Enzyme JALLI, I.S.*; NIJHOUT, H.F.; Duke University, Durham; Duke University, Durham isj@duke.edu

The methionine cycle is a metabolic network that lies at the intersection of many critical cell processes such as DNA synthesis, and DNA and histone methylation. All cellular organisms contain this small yet vital network, but unique variations of the cycle have evolved across species. The evolution of the methionine cycle in plants is set apart from other organisms, because of the enzyme Methionine S-methyltransferase (MMT), which produces S-methyl-L-methionine (SMM). SMM has specialized functions in extant plants, but the evolutionary history of the metabolite and its production is unknown. The current works exploits mathematical modeling of the methionine cycle in Escherichia coli to show that SMM production has a significant stabilizing effect on the methionine cycle. Simulated insertion of the Arabidopsis Thaliana MMT enzyme in the E.coli methionine cycle affords greater robustness to metabolite perturbations in the methionine cycle. This strong stabilizing effect points to an early, purely structural benefit of SMM production. The structural benefit points to a different role of SMM before it was adopted to play its current roles in plant physiology.