C@Fe3O4/NTA-Ni magnetic nanospheres purify histidine-tagged fetidin: A technical note

Abstract

This study reports synthesis of Ni-nitrilotriacetic acid (Ni-NTA) modified carbon nanospheres containing magnetic Fe₃O₄ particles (C@Fe₃O₄), which can act as a general tool to separate and purify histidine-tagged fetidin. In this experiment, C nanospheres are prepared from glucose using the hydrothermal process, magnetic Fe₃O₄ are packed in the porous C nanospheres and Ni-NTA are conjugated to C@Fe₃O₄. C@Fe₃O₄/NTA-Ni nanospheres are about 400 nm in diameter, providing the nanospheres with excellent magnetic response and dispersity. This study separates recombinant fetidin that are engineered to have six consecutive histidine residues (6×His) by treating with C@Fe₃O₄/NTA-Ni magnetic nanospheres. 10 mg of C@Fe₃O₄/NTA-Ni nanospheres can purify up to 2.103 mg of high-purity 6×His-tagged fetidin from 10 ml of crude Escherichia coli lysates. Because of high performance, C@Fe₃O₄/NTA-Ni nanospheres can also be used to separate low concentration 6×His-tagged proteins.

Key words: Magnetic carbon nanosphere, 6×His-tag, fetidin, Ni-chelating.