[Expression, purification and identification for fibronectin C-terminal heparin-binding domain polypeptide in Pichia...

To express and identify fibronectin C-terminal heparin-binding domain (FNCH BD) polypeptides in Pichia pastoris expression system and study its function, the fragment of FNCHBD was amplified by PCR and inserted into pGEM-T vector. After sequenced, the fragment was inserted into pAo815SM vector, and then cloned into the expression vector pPIC9k. The recombinant plasmid was linerarized with restrict enzyme Sal I and transferred into the yeast host cell KM71 and GS115. The positive yeast clone was screened by G418 resistant, and the target protein was induced to express in the medium containing 0.5% methanol. The culture supernatant was collected and then was purified with membrane ultrafiltration and ion exchange chromatography. The purified product was analyzed with mass spectrogram, SDS-PAGE, Western blotting and heparin affinity chromatography. The results showed that the target protein was around 32 kDa and the purity of the product was above 95%. FNCHBD could be specifically recognized by fibronectin polyclonal antibody. These results suggest that FNCHBD could be expressed and purified successfully in Pichia pastoris, which provides a good strategy to further studies.