title: An approach to the production of soluble protein from a fungal gene encoding an aggregation-prone xylanase in Escherichia coli.
abstract: The development of new procedures and protocols that allow researchers to obtain recombinant proteins is of fundamental importance in the biotechnology field. A strategy was explored to overcome inclusion-body formation observed when expressing an aggregation-prone fungal xylanase in Escherichia coli. pHsh is an expression plasmid that uses a synthetic heat-shock (Hsh) promoter, in which gene expression is regulated by an alternative sigma factor (σ(32)). A derivative of pHsh was constructed by fusing a signal peptide to xynA2 gene to facilitate export of the recombinant protein to the periplasm. The xylanase was produced in a soluble form. Three factors were essential to achieving such soluble expression of the xylanase: 1) the target gene was under the control of the Hsh promoter, 2) the gene product was exported into the periplasm, and 3) gene expression was induced by a temperature upshift. For the first time we report the expression of periplasmic proteins under the control of an Hsh promoter regulated by σ(32). One unique feature of this approach was that over 200 copies of the Hsh promoter in an E. coli cell significantly increased the concentration of σ(32). The growth inhibition of the recombinant cells corresponded to an increase in the levels of soluble periplasmic protein. Therefore, an alternative protocol was designed to induce gene expression from pHsh-ex to obtain high levels of active soluble enzymes.
authors.affiliation: Research Center for Biotechnology and Biomass Energy and College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, PR China.
authors.forename: Yilin
authors.initials: Y
authors.lastname: Le
authors.forename: Jingjing
authors.initials: J
authors.lastname: Peng
authors.forename: Huawei
authors.initials: H
authors.lastname: Wu
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Sun
authors.forename: Weilan
authors.initials: W
authors.lastname: Shao
mesh_terms: D001709:Biotechnology / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D043364:Endo-1,4-beta Xylanases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D048168:Escherichia coli K12 / Q000254:growth & development / Q000378:metabolism*; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D005658:Fungi / Q000201:enzymology* / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics*; D005822:Genetic Vectors / Q000235:genetics; D006360:Heat-Shock Proteins / Q000378:metabolism; D002479:Inclusion Bodies / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D033903:Periplasmic Proteins / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D020836:Protein Structure, Quaternary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification; D012808:Sigma Factor / Q000378:metabolism; D012995:Solubility
chemical_list: D005656:Fungal Proteins; D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; C069774:heat-shock sigma factor 32; D043364:Endo-1,4-beta Xylanases