title: Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions.
abstract: For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear how they interplay in the regulation of ETC enzymes under micro-aerobic chemostat conditions. Also, there are diverse results which and how quinones (oxidised/reduced, ubiquinone/other quinones) are controlling the ArcBA two-component system. In the following a mathematical model of the E. coli ETC linked to basic modules for substrate uptake, fermentation product excretion and biomass formation is introduced. The kinetic modelling focusses on regulatory principles of the ETC for varying oxygen conditions in glucose-limited continuous cultures. The model is based on the balance of electron donation (glucose) and acceptance (oxygen or other acceptors). Also, it is able to account for different chemostat conditions due to changed substrate concentrations and dilution rates. The parameter identification process is divided into an estimation and a validation step based on previously published and new experimental data. The model shows that experimentally observed, qualitatively different behaviour of the ubiquinone redox state and the ArcA activity profile in the micro-aerobic range for different experimental conditions can emerge from a single network structure. The network structure features a strong feed-forward effect from the FNR regulatory system to the ArcBA regulatory system via a common control of the dehydrogenases of the ETC. The model supports the hypothesis that ubiquinone but not ubiquinol plays a key role in determining the activity of ArcBA in a glucose-limited chemostat at micro-aerobic conditions.
authors.affiliation: Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.
authors.forename: Sebastian G
authors.initials: SG
authors.lastname: Henkel
authors.affiliation: Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ter Beek
authors.affiliation: Experimental Systems Biology, Max-Planck-Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Steinsiek
authors.affiliation: Experimental Systems Biology, Max-Planck-Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Stagge
authors.affiliation: Experimental Systems Biology, Max-Planck-Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Bettenbrock
authors.affiliation: Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: M Joost Teixeira
authors.initials: MJ
authors.lastname: de Mattos
authors.affiliation: Life Science Research Unit, Université du Luxembourg, Luxembourg, Luxembourg.
authors.forename: Thomas
authors.initials: T
authors.lastname: Sauter
authors.affiliation: Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Sawodny
authors.affiliation: Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Ederer
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D004579:Electron Transport; D045222:Electron Transport Chain Complex Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D007700:Kinetics; D008954:Models, Biological; D010100:Oxygen / Q000502:physiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D045222:Electron Transport Chain Complex Proteins; D029968:Escherichia coli Proteins; D010100:Oxygen