Small Ubiquitin-Like Modifier Protein 3 Enhances the Solubilization of Human Bone Morphogenetic Protein 2 in E. coli

Chaperone-mediated production of active homodimer human bone morphogenetic protein - 2 in E. coli

Human bone morphogenetic protein 2 (hBMP-2) plays a leading role in the process of osteogenesis and is one of the key components of osteoplastic materials, ensuring their high osteoinduction. In order to obtain a homodimeric form hBMP-2 using the E. coli expression system, a number of problems associated with refolding in vitro and purification from monomer and oligomeric forms must be solved. The developed method for co-expression of the target protein with chaperone proteins makes it possible to obtain the biologically active homodimeric form of hBMP-2 in vivo. Purification with simple ion-exchange sorbents without the use of denaturing reagents affecting the structure of the protein molecule provides a chromatographic purity of the product of at least 97%. The expressed hBMP-2 was identified by Western blotting and the LC-ESI-TOF mass spectrometry confirmed its molecular weight of 26052.72 Da. Circular dichroism spectroscopy showed that recombinant hBMP-2 has a native secondary structure.

Electroporation of His-Cre fusion protein triggers a specific recombinase-mediated cassette exchange in HEK 293T cells

Cre recombinase is a widely-used genetic manipulation of genomic DNA. However, the conventional transfection of the DNA vectors expressing the Cre recombinase or viral transduction method yields low transfection efficiencies or insertion mutagenesis. The present paper evaluated whether the direct protein delivery of Cre recombinase through electroporation can induce the Cre-mediated recombination in the HEK 293T cells. Here, the small ubiquitin-related modifier (SUMO) -tagged His-Cre fusion protein was expressed in a soluble pattern in the Eschrichria coli (E.coli) cells, purified using affinity chromatography, and finally electroporated into the HEK 293T cells. These cells were previously transfected with three different Cre reporter vectors. The electroporation of the HEK 293T cells revealed either the activation of EGFP expression, or a decrease in RFP expression, and a concomitant increase in EGFP expression, indicating a desired recombinase-mediated cassette exchange (RMCE) event (conversion of RFP to EGFP), and a biological activity of the purified SUMO-His-Cre protein, which is expected to serve in the Easi-CRISPR-LoxP-mediated genome editing to generate transgenic animal models.

Soluble Production of Human Recombinant VEGF-A121 by Using SUMO Fusion Technology in Escherichia coli

Human recombinant vascular endothelial growth factor-A121 (hrVEGF-A121) has applications in pharmaceutical industry especially in regenerative medicine. Here, we report the expression, purification, and characterization of hrVEGF-A121 in Escherichia coli expression system using human small ubiquitin-related modifier-3 (hSUMO3) fusion partner. Total RNA was isolated from healthy human gingival tissue, VEGF-A121 gene was RT-PCR amplified, and hSUMO3 gene was tagged at N-terminus. The fusion gene (SUMO3-VEGF-A121) was cloned in pET-22b(+) expression vector and transferred into E. coli strains; BL21 codon + and Rosetta-gami B(DE3). The hrVEGF-A121 expression was optimized for temperature, IPTG concentration, and time in Terrific Broth (TB). The positive transformants were sequenced and hrVEGF-A121 nucleotide sequence was submitted to Genbank (Accession No. KT581010). Approximately 40% of total cell protein expression was observed in soluble form on 15% SDS-PAGE. The hSUMO3 was cleaved from hrVEGF-A121 with SUMO protease and purified by Fast Protein Liquid Chromatography using anionic Hi-trap Resource Q column. From 100 ml TB, ~ 25.5% and ~ 6.8 mg of hrVEGF-A121 protein was recovered. The dimerized hrVEGF-A121 was characterized by Native PAGE and Western blot, using human anti-VEGF-A antibody and ESI-MS showed dimeric hrVEGF-A121 at 31,015 Da. The biological activity of hrVEGF-A121 was assessed in vitro by MTT and cell viability assay and observed to be bioactive.