Chemical Synthesis of the Highly Hydrophobic Antiviral Membrane-Associated Protein IFITM3 and Modified Variants
Thibault J Harmand1, Vijaya R Pattabiraman1, Jeffrey W Bode1,2
1Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, Wolfgang Pauli Strasse 10, 8093, Zürich, Switzerland.
Abstract:
Interferon-induced transmembrane protein 3 (IFITM3) is an antiviral transmembrane protein that is thought to serve as the primary factor for inhibiting the replication of a large number of viruses, including West Nile virus, Dengue virus, Ebola virus, and Zika virus. Production of this 14.5 kDa, 133-residue transmembrane protein, especially with essential posttranslational modifications, by recombinant expression is challenging. In this report, we document the chemical synthesis of IFTIM3 in multi-milligram quantities (>15 mg) and the preparation of phosphorylated and fluorescent variants. The synthesis was accomplished by using KAHA ligations, which operate under acidic aqueous/organic mixtures that excel at solubilizing even the exceptionally hydrophobic C-terminal region of IFITM3. The synthetic material is readily incorporated into model vesicles and forms the basis for using synthetic, homogenous IFITM3 and its derivatives for further studying its structure and biological mode of action.
Insights
Chemically synthesizing the antiviral protein Interferon-induced transmembrane protein 3 (IFITM3) in large quantities is now possible. This breakthrough enables further studies into IFITM3
Area of Science:
- Biochemistry
- Molecular Biology
- Virology
Background:
- Interferon-induced transmembrane protein 3 (IFITM3) is a key antiviral protein.
- IFITM3 inhibits replication of viruses like Dengue, Ebola, and Zika.
- Recombinant production of functional IFITM3 is challenging due to its hydrophobic nature and posttranslational modifications.
Purpose of the Study:
- To develop a method for the chemical synthesis of IFITM3.
- To produce multi-milligram quantities of synthetic IFITM3.
- To prepare modified IFITM3 variants (phosphorylated, fluorescent) for further research.
Main Methods:
- Chemical synthesis of IFITM3 using KAHA ligations.
- Utilizing acidic aqueous/organic mixtures to solubilize the hydrophobic C-terminal region.
- Preparation of phosphorylated and fluorescent IFITM3 derivatives.
Main Results:
- Successful multi-milligram scale chemical synthesis of IFITM3 (>15 mg).
- Developed methods for producing phosphorylated and fluorescent IFITM3 variants.
- Synthetic IFITM3 was effectively incorporated into model vesicles.
Conclusions:
- Chemical synthesis provides a viable route for producing large quantities of IFITM3.
- Synthetic, homogenous IFITM3 and its derivatives are valuable tools for structural and mechanistic studies.
- This work overcomes previous limitations in obtaining sufficient quantities of IFITM3 for research.
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