Thermostable Iron Oxide Nanoparticle Synthesis within Recombinant Ferritins from the Piezophilic Hyperthermophile Pyrococcus CH1

Thermostable nanoparticles have great applications in oil/gas industry and catalysis, and are mainly synthesized by heat-resistant polymers. The process of synthesis of these thermostable nanoparticles are tedious and money cost. Here, a novel thermostable ferritin named PcFn, originally from the hyperthermophilic archaeon Pyrococcus yayanosii CH1, was overexpressed in Escherichia coli and purified, which could successfully direct synthesis of thermostable magnetoferritins (M-PcFn) by a facile and one-step method. TEM images show that the protein cage of M-PcFn is intact and the iron oxide cores of M-PcFn with an average core size of 4.7 nm, and magnetic parameters indicate M-PcFn is typical superparamagnetism. Both of the PcFn and M-PcFn can resist the temperature as high as 110 ℃, which are nearly the same as previously reported Pyrococcus furiosus ferritin (PfFn) and its magnetoferritin of M-PfFn, but significantly higher than human H-chain ferritin (HFn) and its magnetoferritin of M-HFn. After heating at 110 ℃ for 30 minutes, the PcFn and M-PcFn still kept their secondary structure and the PcFn retain 87.4% iron uptake activity. This remarkable thermal resistance of PcFn and M-PcFn provides potential application in elevated temperature fields.

Acknowledgements

This work was supported by grants from National Natural Science Foundation of China (nos.: 41574062, 41774076, respectively).