title: Bacterial growth laws reflect the evolutionary importance of energy efficiency.
abstract: We are interested in the balance of energy and protein synthesis in bacterial growth. How has evolution optimized this balance? We describe an analytical model that leverages extensive literature data on growth laws to infer the underlying fitness landscape and to draw inferences about what evolution has optimized in Escherichia coli. Is E. coli optimized for growth speed, energy efficiency, or some other property? Experimental data show that at its replication speed limit, E. coli produces about four mass equivalents of nonribosomal proteins for every mass equivalent of ribosomes. This ratio can be explained if the cell's fitness function is the the energy efficiency of cells under fast growth conditions, indicating a tradeoff between the high energy costs of ribosomes under fast growth and the high energy costs of turning over nonribosomal proteins under slow growth. This model gives insight into some of the complex nonlinear relationships between energy utilization and ribosomal and nonribosomal production as a function of cell growth conditions.
authors.affiliation: Laufer Center for Physical and Quantitative Biology and the Departments of Chemistry and Physics, Stony Brook University, Stony Brook, NY 11794 arijit.maitra@stonybrook.edu dill@laufercenter.org.
authors.forename: Arijit
authors.initials: A
authors.lastname: Maitra
authors.affiliation: Laufer Center for Physical and Quantitative Biology and the Departments of Chemistry and Physics, Stony Brook University, Stony Brook, NY 11794 arijit.maitra@stonybrook.edu dill@laufercenter.org.
authors.forename: Ken A
authors.initials: KA
authors.lastname: Dill
mesh_terms: D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism*; D005075:Biological Evolution; D004734:Energy Metabolism; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000096:biosynthesis; D007700:Kinetics; D008954:Models, Biological; D046908:Peptide Biosynthesis, Nucleic Acid-Independent; D012269:Ribosomal Proteins / Q000096:biosynthesis; D012270:Ribosomes / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D012269:Ribosomal Proteins
keywords: bacterial metabolism; energy efficiency; fitness landscape; growth laws; yield