Engineering of Bio-Adhesive Ligand Containing Recombinant RGD and PHSRN Fibronectin Cell-Binding Domains in Fusion with a Colored Multi Affinity Tag: Simple Approach for Fragment Study from Expression to Adsorption.

Engineering of biomimetic motives have emerged as promising approaches to improving cells' binding properties of biomaterials for tissue engineering and regenerative medicine. In this study, a bio-adhesive ligand including cell-binding domains of human fibronectin (FN) was engineered using recombinant protein technology, a major extracellular matrix (ECM) protein that interacts with a variety of integrins cell-surface's receptors and other ECM proteins through specific binding domains. 9th and 10th fibronectin type III repeat containing Arginine-Glycine-Aspartic acid (RGD) and Pro-His-Ser-Arg-Asn (PHSRN) synergic site (FNIII9-10) were expressed in fusion with a Colored Multi Affinity Tag (CMAT) to develop a simplified production and characterization process. A recombinant fragment was produced in the bacterial system using E. coli with high yield purified protein by double affinity chromatography. Bio-adhesive surfaces were developed by passive coating of produced fragment onto non adhesive surfaces model. The recombinant fusion protein (CMAT-FNIII9/10) demonstrated an accurate monitoring capability during expression purification and adsorption assay. Finally, biological activity of recombinant FNIII9/10 was validated by cellular adhesion assay. Binding to α5ß1 integrins were successfully validated using a produced fragment as a ligand. These results are robust supports to the rational development of bioactivation strategies for biomedical and biotechnological applications.

An improved strategy for easy process monitoring and advanced purification of recombinant proteins.

In this work, a multifunctional expression cassette, termed Multitags, combining different and complementary functionalities, was designed and used to monitor the expression and the purification of two model proteins (Pfu DNA polymerase and Myosin-VIIa- and Rab-Interracting protein : MyRIP). Multitags contains two affinity purification tags, a polyhistidine sequence (10× His) and the streptavidin-binding peptide (SBP) and as a marker tag the heme-binding domain of rat cytochrome b5 followed by the TEV cleavage site. Using the Multitags as fusion partner, more than 90 % of both fusion proteins were produced in soluble form when expressed in Escherichia coli KRX. In addition, high purity (99 %) of recombinant proteins was achieved after two consecutive affinity purification steps. The expression cassette also demonstrated an accurate monitoring capability comparable to that of a dual recognition-based method. The choice of the SBP tag was considered as an integral process that included a method for tag removal. Thus, an immobilized TEV protease fixed on streptavidin-agarose matrix was used for the cleavage of fusion proteins. After digestion, both unprocessed fusion proteins and Multitags were retained on the proteolytic column via their SBP sequence, allowing cleavage and recovery of target proteins on one step. This combined approach may accelerate the development of optimized production processes, while insuring high product quality and a low production cost.

Reprint of: A new tagged-TEV protease: Construction, optimisation of production, purification and test activity.

The Tobacco Etch Virus (TEV) protease is frequently used in the cleavage of recombinant fusion proteins because of its efficiency and high specificity. In this work, we present a new recombinant form of TEV termed Streptag II-TEV for high-level production and purification of TEV protease from Escherichia coli and compare it to the hexahistidine (6xHis) tagged version of TEV. The effects of varying the host strain, the bacterial induction temperature (25, 30 and 37°C) and the IPTG inducer concentration on production and solubility of the two recombinant TEV proteases have been examined. Optimal Streptag II-TEV protein expression were obtained in the E. coli KRX strain under an induction temperature of 25°C in the presence of IPTG at 0.5mM. In these conditions, soluble Streptag II-TEV and 6xHis-TEV proteases accounted for about 25% and 18% of total soluble proteins, respectively. About 70% of Streptag II-TEV and 60% of 6xHis-TEV were detected in the supernatant. Streptag II-TEV protease purifies to near homogeneity (approximately 99%) via a simple, single step Strep-Tactin chromatography purification protocol based on the presence of Streptag II. The higher production of Streptag II-TEV coupled to its purification and cleavage efficiencies make it an attractive alternate to 6xHis-TEV.

A new tagged-TEV protease: construction, optimisation of production, purification and test activity.

The Tobacco Etch Virus (TEV) protease is frequently used in the cleavage of recombinant fusion proteins because of its efficiency and high specificity. In this work, we present a new recombinant form of TEV termed Streptag II-TEV for high-level production and purification of TEV protease from Escherichia coli and compare it to the hexahistidine (6xHis) tagged version of TEV. The effects of varying the host strain, the bacterial induction temperature (25, 30 and 37°C) and the IPTG inducer concentration on production and solubility of the two recombinant TEV proteases have been examined. Optimal Streptag II-TEV protein expression were obtained in the E. coli KRX strain under an induction temperature of 25°C in the presence of IPTG at 0.5 mM. In these conditions, soluble Streptag II-TEV and 6xHis-TEV proteases accounted for about 25% and 18% of total soluble proteins, respectively. About 70% of Streptag II-TEV and 60% of 6xHis-TEV were detected in the supernatant. Streptag II-TEV protease purifies to near homogeneity (approximately 99%) via a simple, single step Strep-Tactin chromatography purification protocol based on the presence of Streptag II. The higher production of Streptag II-TEV coupled to its purification and cleavage efficiencies make it an attractive alternate to 6xHis-TEV.