title: Ubiquitin-intein and SUMO2-intein fusion systems for enhanced protein production and purification.
abstract: Although most commonly used for protein production, expression of soluble and functional recombinant protein in Escherichia coli is still a major challenge. The development and application of fusion tags that can facilitate protein expression and solubility partly solve this problem, however, under most circumstance, the fusion tags have to be removed by proteases in order to use the proteins. Because the tag removal using proteases increases cost and introduces extra purification steps, it remains a significant problem that must be resolved before being widely used in industry production. Ubiquitin and SUMO have been successfully used to enhance protein expression and solubility. In the last decades, intein has also been widely used in protein production for its self-cleavage property, which could help to remove the fusion tag without any protease. Here, we take the advantages of ubiquitin, SUMO2 and intein in protein expression. We constructed tandem ubiquitin-intein and SUMO2-intein fusion tags, and chose human MMP13 (amino acid 104-274) and eGFP as the passenger proteins that fused to the C-terminus of the tags. These constructs were expressed in E. coli and both MMP13 and eGFP expression and solubility were evaluated. Both tags showed the ability to enhance the solubility of MMP13 and eGFP and improve the expression of eGFP, and the SUMO2-intein having a more significant effect. Both ubiquitin-intein-eGFP and SUMO2-intein-eGFP were purified using Ni-NTA column chromatography and self-cleavaged by changing pH. The recombinant un-tagged eGFP were released and eluted with high homogeneity. In summary, ubiquitin-intein and SUMO2-intein are convenient and useful fusion tags that can enhance the expression, solubility and improve the purification process of the model heterologous protein and these tags may have a good prospect in protein production.
authors.affiliation: School of Life Sciences, Tsinghua University, Beijing 100084, PR China.
authors.forename: Zhongyuan
authors.initials: Z
authors.lastname: Wang
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Wang
authors.forename: Yanping
authors.initials: Y
authors.lastname: Wu
authors.forename: Tianyang
authors.initials: T
authors.lastname: Mu
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.forename: Laiqiang
authors.initials: L
authors.lastname: Huang
authors.forename: Xuexun
authors.initials: X
authors.lastname: Fang
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000302:isolation & purification; D006639:Histidine / Q000235:genetics; D006801:Humans; D047668:Inteins; D053509:Matrix Metalloproteinase 13 / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000302:isolation & purification; D025841:Small Ubiquitin-Related Modifier Proteins / Q000235:genetics* / Q000302:isolation & purification; D025801:Ubiquitin / Q000235:genetics* / Q000302:isolation & purification
chemical_list: C471213:His-His-His-His-His-His; D009842:Oligopeptides; D011993:Recombinant Fusion Proteins; C117909:SUMO2 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D025801:Ubiquitin; D049452:Green Fluorescent Proteins; D006639:Histidine; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13