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McCloskey NS, Mammedova A, Liberles DA. PEMPS: a phylogenetic software tool to model the evolution of metabolic pathways. BMC Bioinformatics 2024; 25:244. [PMID: 39026162 DOI: 10.1186/s12859-024-05867-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 07/11/2024] [Indexed: 07/20/2024] Open
Abstract
BACKGROUND Metabolic pathways support the enzyme flux that converts input chemicals into energy and cellular building blocks. With a constant rate of input, steady-state flux is achieved when metabolite concentrations and reaction rates remain constant over time. Individual genes undergo mutation, while selection acts on higher level functions of the pathway, such as steady-state flux where applicable. Modeling the evolution of metabolic pathways through mechanistic sets of ordinary differential equations is a piece of the genotype-phenotype map model for interpreting genetic variation and inter-specific differences. Such models can generate distinct compensatory changes and adaptive changes from directional selection, indicating single nucleotide polymorphisms and fixed differences that could affect phenotype. If used for inference, this would ultimately enable detection of selection on metabolic pathways as well as inference of ancestral states for metabolic pathway function. RESULTS A software tool for simulating the evolution of metabolic pathways based upon underlying biochemistry, phylogenetics, and evolutionary considerations is presented. The Python program, Phylogenetic Evolution of Metabolic Pathway Simulator (PEMPS), implements a mutation-selection framework to simulate the evolution of the pathway over a phylogeny by interfacing with COPASI to calculate the steady-state flux of the metabolic network, introducing mutations as alterations in parameter values according to a model, and calculating a fitness score and corresponding probability of fixation based on the change in steady-state flux value(s). Results from simulations are consistent with a priori expectations of fixation probabilities and systematic change in model parameters. CONCLUSIONS The PEMPS program simulates the evolution of a metabolic pathway with a mutation-selection modeling framework based on criteria like steady-state flux that is designed to work with SBML-formatted kinetic models, and Newick-formatted phylogenetic trees. The Python software is run on the Linux command line and is available at https://github.com/nmccloskey/PEMPS .
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Affiliation(s)
- Nicholas S McCloskey
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA
| | - Ayna Mammedova
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA
| | - David A Liberles
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
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Zonnequin M, Belcour A, Delage L, Siegel A, Blanquart S, Leblanc C, Markov GV. Empirical evidence for metabolic drift in plant and algal lipid biosynthesis pathways. FRONTIERS IN PLANT SCIENCE 2024; 15:1339132. [PMID: 38357267 PMCID: PMC10864609 DOI: 10.3389/fpls.2024.1339132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/15/2024] [Indexed: 02/16/2024]
Abstract
Metabolic pathway drift has been formulated as a general principle to help in the interpretation of comparative analyses between biosynthesis pathways. Indeed, such analyses often indicate substantial differences, even in widespread pathways that are sometimes believed to be conserved. Here, our purpose is to check how much this interpretation fits to empirical data gathered in the field of plant and algal biosynthesis pathways. After examining several examples representative of the diversity of lipid biosynthesis pathways, we explain why it is important to compare closely related species to gain a better understanding of this phenomenon. Furthermore, this comparative approach brings us to the question of how much biotic interactions are responsible for shaping this metabolic plasticity. We end up introducing some model systems that may be promising for further exploration of this question.
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Affiliation(s)
- Maëlle Zonnequin
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M, UMR8227), Station Biologique de Roscoff (SBR), Roscoff, France
| | - Arnaud Belcour
- Univ Rennes, Inria, CNRS, IRISA, Equipe Dyliss, Rennes, France
- Univ. Grenoble Alpes, Inria, Grenoble, France
| | - Ludovic Delage
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M, UMR8227), Station Biologique de Roscoff (SBR), Roscoff, France
| | - Anne Siegel
- Univ Rennes, Inria, CNRS, IRISA, Equipe Dyliss, Rennes, France
| | | | - Catherine Leblanc
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M, UMR8227), Station Biologique de Roscoff (SBR), Roscoff, France
| | - Gabriel V. Markov
- Sorbonne Université, CNRS, Integrative Biology of Marine Models (LBI2M, UMR8227), Station Biologique de Roscoff (SBR), Roscoff, France
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3
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Joo Y, Sung JY, Shin SM, Park SJ, Kim KS, Park KD, Kim SB, Lee DW. A Retro-Aldol Reaction Prompted the Evolvability of a Phosphotransferase System for the Utilization of a Rare Sugar. Microbiol Spectr 2023; 11:e0366022. [PMID: 36786576 PMCID: PMC10101011 DOI: 10.1128/spectrum.03660-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 01/25/2023] [Indexed: 02/15/2023] Open
Abstract
The evolution of the bacterial phosphotransferase system (PTS) linked to glycolysis is dependent on the availability of naturally occurring sugars. Although bacteria exhibit sugar specificities based on carbon catabolite repression, the acquisition and evolvability of the cellular sugar preference under conditions that are suboptimal for growth (e.g., environments rich in a rare sugar) are poorly understood. Here, we generated Escherichia coli mutants via a retro-aldol reaction to obtain progeny that can utilize the rare sugar d-tagatose. We detected a minimal set of adaptive mutations in the d-fructose-specific PTS to render E. coli capable of d-tagatose utilization. These E. coli mutant strains lost the tight regulation of both the d-fructose and N-acetyl-galactosamine PTS following deletions in the binding site of the catabolite repressor/activator protein (Cra) upstream from the fruBKA operon and in the agaR gene, encoding the N-acetylgalactosamine (GalNAc) repressor, respectively. Acquired d-tagatose catabolic pathways then underwent fine-tuned adaptation via an additional mutation in 1-phosphofructose kinase to adjust metabolic fluxes. We determined the evolutionary trajectory at the molecular level, providing insights into the mechanism by which enteric bacteria evolved a substrate preference for the rare sugar d-tagatose. Furthermore, the engineered E. coli mutant strain could serve as an in vivo high-throughput screening platform for engineering non-phosphosugar isomerases to produce rare sugars. IMPORTANCE Microorganisms generate energy through glycolysis, which might have preceded a rapid burst of evolution, including the evolution of cellular respiration in the primordial biosphere. However, little is known about the evolvability of cellular sugar preferences. Here, we generated Escherichia coli mutants via a retro-aldol reaction to obtain progeny that can utilize the rare sugar d-tagatose. Consequently, we identified mutational hot spots and determined the evolutionary trajectory at the molecular level. This provided insights into the mechanism by which enteric bacteria evolved substrate preferences for various sugars, accounting for the widespread occurrence of these taxa. Furthermore, the adaptive laboratory evolution-induced cellular chassis could serve as an in vivo high-throughput screening platform for engineering tailor-made non-phosphorylated sugar isomerases to produce low-calorigenic rare sugars showing antidiabetic, antihyperglycemic, and antitumor activities.
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Affiliation(s)
- Yunhye Joo
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Jae-Yoon Sung
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Sun-Mi Shin
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Sun Jun Park
- Brain Science Institute, Korea Institute of Science & Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
| | - Kyoung Su Kim
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Ki Duk Park
- Brain Science Institute, Korea Institute of Science & Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, Republic of Korea
| | - Seong-Bo Kim
- Bio-Living Engineering Major, Global Leaders College, Yonsei University, Seoul, Republic of Korea
| | - Dong-Woo Lee
- Department of Biotechnology, Yonsei University, Seoul, Republic of Korea
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4
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Liberles DA. The Memory Problem for Neutral Mutational Models of Evolution. J Mol Evol 2023; 91:2-5. [PMID: 36562800 DOI: 10.1007/s00239-022-10084-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
Models for the evolution of various phenotypes are sometimes constructed with an assumption that mutational effects will be symmetrically distributed about a static mean. This model produces a memory effect that over long evolutionary times results in an expectation that randomized sequences underlying the genetic architecture of the trait will on average retain the ancestral phenotype. This expectation is unrealistic and also inconsistent with our current understanding of processes of molecular evolution.
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Affiliation(s)
- David A Liberles
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
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5
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Venkat K, Hoyos M, Haycocks JR, Cassidy L, Engelmann B, Rolle-Kampczyk U, von Bergen M, Tholey A, Grainger DC, Papenfort K. A dual-function RNA balances carbon uptake and central metabolism in Vibrio cholerae. EMBO J 2021; 40:e108542. [PMID: 34612526 PMCID: PMC8672173 DOI: 10.15252/embj.2021108542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 11/22/2022] Open
Abstract
Bacterial small RNAs (sRNAs) are well known to modulate gene expression by base pairing with trans‐encoded transcripts and are typically non‐coding. However, several sRNAs have been reported to also contain an open reading frame and thus are considered dual‐function RNAs. In this study, we discovered a dual‐function RNA from Vibrio cholerae, called VcdRP, harboring a 29 amino acid small protein (VcdP), as well as a base‐pairing sequence. Using a forward genetic screen, we identified VcdRP as a repressor of cholera toxin production and link this phenotype to the inhibition of carbon transport by the base‐pairing segment of the regulator. By contrast, we demonstrate that the VcdP small protein acts downstream of carbon transport by binding to citrate synthase (GltA), the first enzyme of the citric acid cycle. Interaction of VcdP with GltA results in increased enzyme activity and together VcdR and VcdP reroute carbon metabolism. We further show that transcription of vcdRP is repressed by CRP allowing us to provide a model in which VcdRP employs two different molecular mechanisms to synchronize central metabolism in V. cholerae.
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Affiliation(s)
- Kavyaa Venkat
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Mona Hoyos
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - James Rj Haycocks
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Liam Cassidy
- Systematic Proteome Research & Bioanalytics, University of Kiel, Kiel, Germany
| | | | | | | | - Andreas Tholey
- Systematic Proteome Research & Bioanalytics, University of Kiel, Kiel, Germany
| | - David C Grainger
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Kai Papenfort
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany.,Microverse Cluster, Friedrich Schiller University Jena, Jena, Germany
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6
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Schmidt CA, Fisher-Wellman KH, Neufer PD. From OCR and ECAR to energy: Perspectives on the design and interpretation of bioenergetics studies. J Biol Chem 2021; 297:101140. [PMID: 34461088 PMCID: PMC8479256 DOI: 10.1016/j.jbc.2021.101140] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Biological energy transduction underlies all physiological phenomena in cells. The metabolic systems that support energy transduction have been of great interest due to their association with numerous pathologies including diabetes, cancer, rare genetic diseases, and aberrant cell death. Commercially available bioenergetics technologies (e.g., extracellular flux analysis, high-resolution respirometry, fluorescent dye kits, etc.) have made practical assessment of metabolic parameters widely accessible. This has facilitated an explosion in the number of studies exploring, in particular, the biological implications of oxygen consumption rate (OCR) and substrate level phosphorylation via glycolysis (i.e., via extracellular acidification rate (ECAR)). Though these technologies have demonstrated substantial utility and broad applicability to cell biology research, they are also susceptible to historical assumptions, experimental limitations, and other caveats that have led to premature and/or erroneous interpretations. This review enumerates various important considerations for designing and interpreting cellular and mitochondrial bioenergetics experiments, some common challenges and pitfalls in data interpretation, and some potential "next steps" to be taken that can address these highlighted challenges.
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Affiliation(s)
- Cameron A Schmidt
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Kelsey H Fisher-Wellman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; Departments of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA; Departments of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
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7
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High-throughput insertional mutagenesis reveals novel targets for enhancing lipid accumulation in Nannochloropsis oceanica. Metab Eng 2021; 66:239-258. [PMID: 33971293 DOI: 10.1016/j.ymben.2021.04.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/07/2021] [Accepted: 04/18/2021] [Indexed: 12/17/2022]
Abstract
The microalga Nannochloropsis oceanica is considered a promising platform for the sustainable production of high-value lipids and biofuel feedstocks. However, current lipid yields of N. oceanica are too low for economic feasibility. Gaining fundamental insights into the lipid metabolism of N. oceanica could open up various possibilities for the optimization of this species through genetic engineering. Therefore, the aim of this study was to discover novel genes associated with an elevated neutral lipid content. We constructed an insertional mutagenesis library of N. oceanica, selected high lipid mutants by five rounds of fluorescence-activated cell sorting, and identified disrupted genes using a novel implementation of a rapid genotyping procedure. One particularly promising mutant (HLM23) was disrupted in a putative APETALA2-like transcription factor gene. HLM23 showed a 40%-increased neutral lipid content, increased photosynthetic performance, and no growth impairment. Furthermore, transcriptome analysis revealed an upregulation of genes related to plastidial fatty acid biosynthesis, glycolysis and the Calvin-Benson-Bassham cycle in HLM23. Insights gained in this work can be used in future genetic engineering strategies for increased lipid productivity of Nannochloropsis.
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8
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Muñoz-Gómez SA, Bilolikar G, Wideman JG, Geiler-Samerotte K. Constructive Neutral Evolution 20 Years Later. J Mol Evol 2021; 89:172-182. [PMID: 33604782 PMCID: PMC7982386 DOI: 10.1007/s00239-021-09996-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022]
Abstract
Evolution has led to a great diversity that ranges from elegant simplicity to ornate complexity. Many complex features are often assumed to be more functional or adaptive than their simpler alternatives. However, in 1999, Arlin Stolzfus published a paper in the Journal of Molecular Evolution that outlined a framework in which complexity can arise through a series of non-adaptive steps. He called this framework Constructive Neutral Evolution (CNE). Despite its two-decade-old roots, many evolutionary biologists still appear to be unaware of this explanatory framework for the origins of complexity. In this perspective piece, we explain the theory of CNE and how it changes the order of events in narratives that describe the evolution of complexity. We also provide an extensive list of cellular features that may have become more complex through CNE. We end by discussing strategies to determine whether complexity arose through neutral or adaptive processes.
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Affiliation(s)
- Sergio A Muñoz-Gómez
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
| | - Gaurav Bilolikar
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Jeremy G Wideman
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Kerry Geiler-Samerotte
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
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9
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Selberg AGA, Gaucher EA, Liberles DA. Ancestral Sequence Reconstruction: From Chemical Paleogenetics to Maximum Likelihood Algorithms and Beyond. J Mol Evol 2021; 89:157-164. [PMID: 33486547 PMCID: PMC7828096 DOI: 10.1007/s00239-021-09993-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 01/04/2021] [Indexed: 12/13/2022]
Abstract
As both a computational and an experimental endeavor, ancestral sequence reconstruction remains a timely and important technique. Modern approaches to conduct ancestral sequence reconstruction for proteins are built upon a conceptual framework from journal founder Emile Zuckerkandl. On top of this, work on maximum likelihood phylogenetics published in Journal of Molecular Evolution in 1996 was one of the first approaches for generating maximum likelihood ancestral sequences of proteins. From its computational history, future model development needs as well as potential applications in areas as diverse as computational systems biology, molecular community ecology, infectious disease therapeutics and other biomedical applications, and biotechnology are discussed. From its past in this journal, there is a bright future for ancestral sequence reconstruction in the field of evolutionary biology.
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Affiliation(s)
- Avery G A Selberg
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA
| | - Eric A Gaucher
- Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - David A Liberles
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
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10
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Liberles DA, Chang B, Geiler-Samerotte K, Goldman A, Hey J, Kaçar B, Meyer M, Murphy W, Posada D, Storfer A. Emerging Frontiers in the Study of Molecular Evolution. J Mol Evol 2020; 88:211-226. [PMID: 32060574 PMCID: PMC7386396 DOI: 10.1007/s00239-020-09932-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A collection of the editors of Journal of Molecular Evolution have gotten together to pose a set of key challenges and future directions for the field of molecular evolution. Topics include challenges and new directions in prebiotic chemistry and the RNA world, reconstruction of early cellular genomes and proteins, macromolecular and functional evolution, evolutionary cell biology, genome evolution, molecular evolutionary ecology, viral phylodynamics, theoretical population genomics, somatic cell molecular evolution, and directed evolution. While our effort is not meant to be exhaustive, it reflects research questions and problems in the field of molecular evolution that are exciting to our editors.
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Affiliation(s)
- David A Liberles
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
| | - Belinda Chang
- Department of Ecology and Evolutionary Biology and Department of Cell and Systems Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada
| | - Kerry Geiler-Samerotte
- Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Aaron Goldman
- Department of Biology, Oberlin College and Conservatory, K123 Science Center, 119 Woodland Street, Oberlin, OH, 44074, USA
| | - Jody Hey
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA
| | - Betül Kaçar
- Department of Molecular and Cell Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Michelle Meyer
- Department of Biology, Boston College, Chestnut Hill, MA, 02467, USA
| | - William Murphy
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, 77843, USA
| | - David Posada
- Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
| | - Andrew Storfer
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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11
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Aguilar-Rodríguez J, Wagner A. Metabolic Determinants of Enzyme Evolution in a Genome-Scale Bacterial Metabolic Network. Genome Biol Evol 2018; 10:3076-3088. [PMID: 30351420 PMCID: PMC6257574 DOI: 10.1093/gbe/evy234] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2018] [Indexed: 11/12/2022] Open
Abstract
Different genes and proteins evolve at very different rates. To identify the factors that explain these differences is an important aspect of research in molecular evolution. One such factor is the role a protein plays in a large molecular network. Here, we analyze the evolutionary rates of enzyme-coding genes in the genome-scale metabolic network of Escherichia coli to find the evolutionary constraints imposed by the structure and function of this complex metabolic system. Central and highly connected enzymes appear to evolve more slowly than less connected enzymes, but we find that they do so as a by-product of their high abundance, and not because of their position in the metabolic network. In contrast, enzymes catalyzing reactions with high metabolic flux-high substrate to product conversion rates-evolve slowly even after we account for their abundance. Moreover, enzymes catalyzing reactions that are difficult to by-pass through alternative pathways, such that they are essential in many different genetic backgrounds, also evolve more slowly. Our analyses show that an enzyme's role in the function of a metabolic network affects its evolution more than its place in the network's structure. They highlight the value of a system-level perspective for studies of molecular evolution.
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Affiliation(s)
- José Aguilar-Rodríguez
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- Department of Biology, Stanford University, Stanford, CA and Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- The Santa Fe Institute, Santa Fe, New Mexico
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12
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Orlenko A, Chi PB, Liberles DA. Characterizing the roles of changing population size and selection on the evolution of flux control in metabolic pathways. BMC Evol Biol 2017; 17:117. [PMID: 28545395 PMCID: PMC5445498 DOI: 10.1186/s12862-017-0962-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 05/09/2017] [Indexed: 12/20/2022] Open
Abstract
Background Understanding the genotype-phenotype map is fundamental to our understanding of genomes. Genes do not function independently, but rather as part of networks or pathways. In the case of metabolic pathways, flux through the pathway is an important next layer of biological organization up from the individual gene or protein. Flux control in metabolic pathways, reflecting the importance of mutation to individual enzyme genes, may be evolutionarily variable due to the role of mutation-selection-drift balance. The evolutionary stability of rate limiting steps and the patterns of inter-molecular co-evolution were evaluated in a simulated pathway with a system out of equilibrium due to fluctuating selection, population size, or positive directional selection, to contrast with those under stabilizing selection. Results Depending upon the underlying population genetic regime, fluctuating population size was found to increase the evolutionary stability of rate limiting steps in some scenarios. This result was linked to patterns of local adaptation of the population. Further, during positive directional selection, as with more complex mutational scenarios, an increase in the observation of inter-molecular co-evolution was observed. Conclusions Differences in patterns of evolution when systems are in and out of equilibrium, including during positive directional selection may lead to predictable differences in observed patterns for divergent evolutionary scenarios. In particular, this result might be harnessed to detect differences between compensatory processes and directional processes at the pathway level based upon evolutionary observations in individual proteins. Detecting functional shifts in pathways reflects an important milestone in predicting when changes in genotypes result in changes in phenotypes. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0962-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alena Orlenko
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.,Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
| | - Peter B Chi
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.,Department of Mathematics and Computer Science, Ursinus College, Collegeville, PA, 19426, USA
| | - David A Liberles
- Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA. .,Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA.
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13
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Orlenko A, Teufel AI, Chi PB, Liberles DA. Selection on metabolic pathway function in the presence of mutation-selection-drift balance leads to rate-limiting steps that are not evolutionarily stable. Biol Direct 2016; 11:31. [PMID: 27393343 PMCID: PMC4938953 DOI: 10.1186/s13062-016-0133-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/02/2016] [Indexed: 11/15/2022] Open
Abstract
Background While commonly assumed in the biochemistry community that the control of metabolic pathways is thought to be critical to cellular function, it is unclear if metabolic pathways generally have evolutionarily stable rate limiting (flux controlling) steps. Results A set of evolutionary simulations using a kinetic model of a metabolic pathway was performed under different conditions to evaluate the evolutionary stability of rate limiting steps. Simulations used combinations of selection for steady state flux, selection against the cost of molecular biosynthesis, and selection against the accumulation of high concentrations of a deleterious intermediate. Two mutational regimes were used, one with mutations that on average were neutral to molecular phenotype and a second with a preponderance of activity-destroying mutations. The evolutionary stability of rate limiting steps was low in all simulations with non-neutral mutational processes. Clustering of parameter co-evolution showed divergent inter-molecular evolutionary patterns under different evolutionary regimes. Conclusions This study provides a null model for pathway evolution when compensatory processes dominate with potential applications to predicting pathway functional change. This result also suggests a possible mechanism in which studies in statistical genetics that aim to associate a genotype to a phenotype assuming independent action of variants may be mis-specified through a mis-characterization of the link between individual gene function and pathway function. A better understanding of the genotype-phenotype map has potential applications in differentiating between compensatory changes and directional selection on pathways as well as detecting SNPs and fixed differences that might have phenotypic effects. Reviewers This article was reviewed by Arne Elofsson, David Ardell, and Shamil Sunyaev. Electronic supplementary material The online version of this article (doi:10.1186/s13062-016-0133-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alena Orlenko
- Center for Computational Genetics and Genomics and Department of Biology, Temple University, Bio-Life Building, 1900 N. 12th Street, Philadelphia, PA, 19122-1801, USA.,Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
| | - Ashley I Teufel
- Center for Computational Genetics and Genomics and Department of Biology, Temple University, Bio-Life Building, 1900 N. 12th Street, Philadelphia, PA, 19122-1801, USA.,Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA
| | - Peter B Chi
- Center for Computational Genetics and Genomics and Department of Biology, Temple University, Bio-Life Building, 1900 N. 12th Street, Philadelphia, PA, 19122-1801, USA.,Department of Mathematics and Computer Science, Ursinus College, Collegeville, PA, 19426, USA
| | - David A Liberles
- Center for Computational Genetics and Genomics and Department of Biology, Temple University, Bio-Life Building, 1900 N. 12th Street, Philadelphia, PA, 19122-1801, USA. .,Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA.
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