Novel Application of Magnetic Protein: Convenient One-Step Purification and Immobilization of Proteins.

Recently, a magnetic protein was discovered, and a multimeric magnetosensing complex was validated, which may form the basis of magnetoreception. In this study, the magnetic protein was firstly used in biotechnology application, and a novel convenient one-step purification and immobilization method was established. A universal vector and three linker patterns were developed for fusion expression of magnetic protein and target protein. The magnetic protein was absorbed by iron beads, followed by target protein aggregation, purification, and immobilization. GFP, employed as a reporter protein, was successfully purified from cell lysate. Subsequently, three enzymes (lipase, α-L-arabinofuranosidase, pullulanase) with different molecular sizes testified the versatility of this magnetic-based approach. The specific activities of the purified enzymes were distinctly higher than those of the traditionally purified enzymes using affinity chromatography. The lipase immobilized on iron beads presented improved thermostability and enhanced pH tolerance compared to the free enzyme. The immobilized lipase could be easily recovered and reused for maximum utilization. After 20 cycles of reutilization, the magnetically immobilized lipase retained 71% of its initial activity. This investigation may help introduce magnetic protein into biotechnology applications, and the one-step purification and immobilization method may serve to illustrate an economically viable process for industry.