title: Photosynthetic fuel for heterologous enzymes: the role of electron carrier proteins.
abstract: Plants, cyanobacteria, and algae generate a surplus of redox power through photosynthesis, which makes them attractive for biotechnological exploitations. While central metabolism consumes most of the energy, pathways introduced through metabolic engineering can also tap into this source of reducing power. Recent work on the metabolic engineering of photosynthetic organisms has shown that the electron carriers such as ferredoxin and flavodoxin can be used to couple heterologous enzymes to photosynthetic reducing power. Because these proteins have a plethora of interaction partners and rely on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic context.
authors.affiliation: Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
authors.forename: Silas Busck
authors.initials: SB
authors.lastname: Mellor
authors.affiliation: Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Vavitsas
authors.affiliation: Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
authors.forename: Agnieszka Zygadlo
authors.initials: AZ
authors.lastname: Nielsen
authors.affiliation: Copenhagen Plant Science Center, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark. peje@plen.ku.dk.
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Jensen
mesh_terms: D004579:Electron Transport; D004583:Electrons; D004798:Enzymes / Q000378:metabolism*; D060847:Metabolic Engineering; D010788:Photosynthesis; D010940:Plant Proteins / Q000378:metabolism*
chemical_list: D004798:Enzymes; D010940:Plant Proteins
keywords: Cytochrome P450; Ferredoxin; Flavodoxin; Metabolic engineering; Photosynthesis; Synthetic biology