title: Impact of rare codons and the functional coproduction of rate-limiting tRNAs on recombinant protein production in Bacillus megaterium.
abstract: The Gram-positive bacterium Bacillus megaterium was systematically developed for the plasmid-based production of recombinant proteins at the gram-per-liter scale. The amount of protein produced per cell was found strongly correlated to the codon usage of the heterologous gene of interest in comparison to the codon usage of B. megaterium. For analyzing the influence of rare codons on the translational efficiency and protein production in B. megaterium, a test system using the gene for the green fluorescent protein (GFP) as reporter was established. For this purpose, four consecutive identical codons were introduced into the 5' end of gfp and the resulting variations in GFP formation were quantified. Introduction of the rare codons GCC, CGG, and ACC for alanine, arginine, and threonine reduced GFP production 2.1-, 3.3-, and 1.7-fold in comparison to the favored codons GCU, CGU, and ACA, respectively. Coexpression of the corresponding rare codon tRNA (rctRNA) genes improved GFP production 4.2-, 2.7-, and 1.7-fold, respectively. The system was applied to the production of a formate dehydrogenase (FDH) from Mycobacterium vaccae and an extracellular hydrolase (TFH) from Thermobifida fusca. Coexpression of one to three different rctRNA genes resulted in an up to 18-fold increased protein production. Interestingly, rctRNA gene coexpression also elevated the production of M. vaccae FDH and T. fusca TFH from codon optimized genes, indicating a general positive effect by rctRNA gene overexpression on the protein production in B. megaterium. Thus, the basis for a B. megaterium enhanced production strain coexpressing rctRNA genes was laid.
authors.affiliation: Institute of Microbiology, Technische Universität Braunschweig, Spielmannstraße 7, 38106, Braunschweig, Germany.
authors.forename: Constanze
authors.initials: C
authors.lastname: Finger
authors.affiliation: Institute of Microbiology, Technische Universität Braunschweig, Spielmannstraße 7, 38106, Braunschweig, Germany.|PROTAGEN AG, Otto-Hahn-Straße 15, 44227, Dortmund, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Gamer
authors.affiliation: Institute of Microbiology, Technische Universität Braunschweig, Spielmannstraße 7, 38106, Braunschweig, Germany.
authors.forename: Saskia
authors.initials: S
authors.lastname: Klunkelfuß
authors.affiliation: German Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7, 38124, Braunschweig, Germany.
authors.forename: Boyke
authors.initials: B
authors.lastname: Bunk
authors.affiliation: Institute of Microbiology, Technische Universität Braunschweig, Spielmannstraße 7, 38106, Braunschweig, Germany. r.biedendieck@tu-bs.de.|Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, 38106, Braunschweig, Germany. r.biedendieck@tu-bs.de.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Biedendieck
mesh_terms: D039903:Actinobacteria / Q000201:enzymology / Q000235:genetics; D001410:Bacillus megaterium / Q000235:genetics / Q000378:metabolism*; D003062:Codon; D005560:Formate Dehydrogenases / Q000235:genetics / Q000378:metabolism; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D009161:Mycobacterium / Q000201:enzymology / Q000235:genetics; D014176:Protein Biosynthesis; D015202:Protein Engineering / Q000379:methods*; D012343:RNA, Transfer / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D003062:Codon; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D012343:RNA, Transfer; D005560:Formate Dehydrogenases; D006867:Hydrolases
keywords: Bacillus megaterium; Rare codon cluster; Recombinant protein production; tRNA genes