Ionic liquids based on unnatural amino acids, preparation methods thereof, and applications thereof

A combination for preparing a protein comprising an unnatural amino acid, comprising:

• (1) one or more aminoacyl-tRNA synthetases capable of binding to a mutated tRNA;
• (2) one or more mutated tRNAs with an anti-codon loop mutated to complement a termination codon;
• and
• (3) an unnatural amino acid-based ionic liquid, which is an unnatural amino acid-choline ionic liquid, produced through chemical synthesis using choline and the unnatural amino acid as raw materials;
• wherein the aminoacyl-tRNA synthetase(s) in (1) is/are capable of producing aminoacyl-tRNA by binding the unnatural amino acid to the mutated tRNA(s) in (2);
• and
• the unnatural amino acid-based ionic liquid in (3) exhibits enhanced solubility and/or bioavailability compared to the unnatural amino acid;
• the aminoacyl-tRNA synthetase is MmPylRs from Methanosarcina mazei, and the mutated tRNA is tRNAMmPylUCA;
• the aminoacyl-tRNA synthetase is EcLeuRs from Escherichia coli, and the mutated tRNA is tRNAEcLeuCUA;
• the aminoacyl-tRNA synthetase is EcTyrRs from Escherichia coli, and the mutated tRNA is tRNAEcTyrUUA.