title: Expanding the Genetic Code of a Photoautotrophic Organism.
abstract: The photoautotrophic freshwater cyanobacterium Synechococcus elongatus is widely used as a chassis for biotechnological applications as well as a photosynthetic bacterial model. In this study, a method for expanding the genetic code of this cyanobacterium has been established, thereby allowing the incorporation of unnatural amino acids into proteins. This was achieved through UAG stop codon suppression, using an archaeal pyrrolysyl orthogonal translation system. We demonstrate incorporation of unnatural amino acids into green fluorescent protein with 20 ± 3.5% suppression efficiency. The introduced components were shown to be orthogonal to the host translational machinery. In addition, we observed that no significant growth impairment resulted from the integration of the system. To interpret the observations, we modeled and investigated the competition over the UAG codon between release factor 1 and pyl-tRNACUA. On the basis of the model results, and the fact that 39.6% of the stop codons in the S. elongatus genome are UAG stop codons, the suppression efficiency in S. elongatus is unexpectedly high. The reason for this unexpected suppression efficiency has yet to be determined.
authors.affiliation: Department of Life Sciences and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 84105, Israel.
authors.forename: Yonatan
authors.identifier: 0000-0002-0465-9393
authors.initials: Y
authors.lastname: Chemla
authors.affiliation: Department of Life Sciences and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 84105, Israel.
authors.forename: Mor
authors.initials: M
authors.lastname: Friedman
authors.affiliation: Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Mathias
authors.initials: M
authors.lastname: Heltberg
authors.affiliation: Department of Life Sciences and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 84105, Israel.
authors.forename: Anna
authors.initials: A
authors.lastname: Bakhrat
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University , Ramat-Gan 5290002, Israel.
authors.forename: Elad
authors.initials: E
authors.lastname: Nagar
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University , Ramat-Gan 5290002, Israel.
authors.forename: Rakefet
authors.initials: R
authors.lastname: Schwarz
authors.affiliation: Niels Bohr Institute, University of Copenhagen , Blegdamsvej 17, 2100 Copenhagen, Denmark.
authors.forename: Mogens Høgh
authors.initials: MH
authors.lastname: Jensen
authors.affiliation: Department of Life Sciences and Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 84105, Israel.
authors.forename: Lital
authors.identifier: 0000-0002-3805-8625
authors.initials: L
authors.lastname: Alfonta
mesh_terms: D018388:Codon, Terminator; D005798:Genes, Bacterial; D005815:Genetic Code; D046940:Synechococcus / Q000235:genetics*
chemical_list: D018388:Codon, Terminator