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Extractive solubilization, structural change, and functional conversion of cytochrome c in ionic liquids via crown
Kojiro Shimojo1, Noriho Kamiya, Fumito Tani
1Division of Environment and Radiation Sciences, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Tokai-mura, Ibaraki, 319-1195, Japan. shimojo.kojiro@ jaea.go.jp
Analytical Chemistry
|November 16, 2006
Summary
Dicyclohexano-18-crown-6 facilitates heme protein transfer into ionic liquids, enabling cytochrome c
Area of Science:
- Biochemistry
- Physical Chemistry
- Materials Science
Background:
- Heme proteins play crucial roles in biological electron transfer and enzymatic catalysis.
- Efficient extraction and stabilization of proteins in non-aqueous media are challenging.
- Ionic liquids offer unique solvation properties for biomolecules.
Purpose of the Study:
- To investigate the extraction of heme proteins from aqueous solutions into ionic liquids using dicyclohexano-18-crown-6 (DCH18C6).
- To elucidate the structure-function relationship of cytochrome c (Cyt-c) when dissolved in ionic liquids.
- To explore the potential of ionic liquids for modifying protein function.
Main Methods:
- Supramolecular complexation of lysine-rich proteins with DCH18C6.
- Extraction of protein-DCH18C6 complexes into various ionic liquids.
- Spectroscopic characterization (UV-visible, CD, resonance Raman) of Cyt-c in ionic liquids.
- Assessment of peroxidase activity of Cyt-c.
Main Results:
- DCH18C6 enables efficient transfer of Lys-rich proteins into ionic liquids via complexation.
- Hydroxyl group-containing ionic liquids with DCH18C6 achieve quantitative partitioning of Cyt-c.
- Spectroscopic data reveal Met 80 ligand replacement and induction of a non-natural heme structure in Cyt-c within ionic liquids.
- Solubilization in ionic liquids converts Cyt-c from an electron-transfer protein to a peroxidase with enhanced H2O2 affinity.
Conclusions:
- DCH18C6 is effective for transferring heme proteins into ionic liquids.
- Ionic liquid environment significantly alters Cyt-c structure and converts its function to peroxidase.
- This approach offers a novel method for protein functionalization and applications in biocatalysis.
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