title: Effect of codon-optimized E. coli signal peptides on recombinant Bacillus stearothermophilus maltogenic amylase periplasmic localization, yield and activity.
abstract: Recombinant proteins can be targeted to the Escherichia coli periplasm by fusing them to signal peptides. The popular pET vectors facilitate fusion of target proteins to the PelB signal. A systematic comparison of the PelB signal with native E. coli signal peptides for recombinant protein expression and periplasmic localization is not reported. We chose the Bacillus stearothermophilus maltogenic amylase (MA), an industrial enzyme widely used in the baking and brewing industry, as a model protein and analyzed the competence of seven, codon-optimized, E. coli signal sequences to translocate MA to the E. coli periplasm compared to PelB. MA fusions to three of the signals facilitated enhanced periplasmic localization of MA compared to the PelB fusion. Interestingly, these three fusions showed greatly improved MA yields and between 18- and 50-fold improved amylase activities compared to the PelB fusion. Previously, non-optimal codon usage in native E. coli signal peptide sequences has been reported to be important for protein stability and activity. Our results suggest that E. coli signal peptides with optimal codon usage could also be beneficial for heterologous protein secretion to the periplasm. Moreover, such fusions could even enhance activity rather than diminish it. This effect, to our knowledge has not been previously documented. In addition, the seven vector platform reported here could also be used as a screen to identify the best signal peptide partner for other recombinant targets of interest.
authors.affiliation: Anthem Biosciences Pvt. Ltd, #49, Bommasandra Industrial Area Phase-I, Hosur Road, Bangalore, 560099, India, shalaka.s@anthembio.com.
authors.forename: Shalaka
authors.initials: S
authors.lastname: Samant
authors.forename: Gunja
authors.initials: G
authors.lastname: Gupta
authors.forename: Subbulakshmi
authors.initials: S
authors.lastname: Karthikeyan
authors.forename: Saiful F
authors.initials: SF
authors.lastname: Haq
authors.forename: Ayyappan
authors.initials: A
authors.lastname: Nair
authors.forename: Ganesh
authors.initials: G
authors.lastname: Sambasivam
authors.forename: Sunilkumar
authors.initials: S
authors.lastname: Sukumaran
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003062:Codon; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression; D001411:Geobacillus stearothermophilus / Q000201:enzymology* / Q000235:genetics; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D019897:Periplasm / Q000201:enzymology* / Q000378:metabolism; D015202:Protein Engineering; D021382:Protein Sorting Signals; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003062:Codon; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D006026:Glycoside Hydrolases; C120909:glucan 1,4-alpha-maltohydrolase