Recombinant expression and purification of cytoplasmic domain of syndecan-2 proteoglycan

The cytoplasmic domain of syndecan-2, a type I transmembrane heparan sulfate proteoglycan, was over-expressed as a fused form with the ubiquitin molecule in Rosetta2(DE3)pLysS, a special strain of Escherichia coli, and the fusion protein was purified using immobilized metal affinity chromatography (IMAC). The cytoplasmic domain was released from its fusion partner by using yeast ubiquitin hydrolase (YUH), and subsequently purified by reverse phase chromatography. The integrity of the resulting peptide fragment was checked by MALDI-TOF mass and NMR spectroscopy. The final yields of the target peptide were around 2 and 1.5 mg per liter of LB and minimal media, respectively. The recombinant expression and purification of this domain will enable its structural and functional studies using multidimensional NMR spectroscopy and X-ray crystallography.