A Two-Enzyme Adaptive Unit within Bacterial Folate Metabolism.

Andrew F Schober, Andrew D Mathis, Christine Ingle, Junyoung O Park, Li Chen, Joshua D Rabinowitz, Ivan Junier, Olivier Rivoire, Kimberly A Reynolds

Journal: Cell reports 2020;27(11):3359-3370.e7

PMID: 31189117

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Abstract

Enzyme function and evolution are influenced by the larger context of a metabolic pathway. Deleterious mutations or perturbations in one enzyme can often be compensated by mutations to others. We used comparative genomics and experiments to examine evolutionary interactions with the essential metabolic enzyme dihydrofolate reductase (DHFR). Analyses of synteny and co-occurrence across bacterial species indicate that DHFR is coupled to thymidylate synthase (TYMS) but relatively independent from the rest of folate metabolism. Using quantitative growth rate measurements and forward evolution in Escherichia coli, we demonstrate that the two enzymes adapt as a relatively independent unit in response to antibiotic stress. Metabolomic profiling revealed that TYMS activity must not exceed DHFR activity to prevent the depletion of reduced folates and the accumulation of the intermediate dihydrofolate. Comparative genomics analyses identified >200 gene pairs with similar statistical signatures of modular co-evolution, suggesting that cellular pathways may be decomposable into small adaptive units.

Address: The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.; The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.; Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC-IMAG, F-38000 Grenoble, France.; Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, F-75005 Paris, France.; The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address: [email protected].

DOI: 10.1016/j.celrep.2019.05.030