METHIONYL TRNA SYNTHETASE FOR BIOSYNTHESIS OF PHOTOMETHIONINE-LABELED PROTEIN AND METHOD FOR PREPARING PHOTOACTIVE PROTEIN G VARIANT USING SAME

摘要

The present invention relates to a methionyl tRNA synthetase (MRS) for the biosynthesis of a photomethionine-labeled protein and a method for preparing a photoactive protein G variant using same and, more particularly, to an MRS variant in which alanine (SEQ ID NO: 12) is substituted by glycine, leucine (SEQ ID NO: 13) by serine, tyrosine (SEQ ID NO: 260) by phenylalanine, isoleucine (SEQ ID NO: 297) by valine, and histidine (SEQ ID NO: 301) by leucine from the N-terminus of the amino acid sequence of a wild-type Escherichia coli methionyl tRNA synthetase. The MRS variant effectively confirms the biosynthesis of a photomethionine-labeled target protein and thus can be utilized for the biosynthesis of a photomethionine-labeled target protein. In addition, a photomethionine-introduced protein G variant, in which a plasmid encoding the MRS variant (MRS5m) and a PG-C3 plasmid, in which, in the third antibody-binding domain of protein G, SEQ ID NOs: 32, 35, and 40 are substituted by a methionine (Met) residue and SEQ ID NO: 37 by an arginine (Arg) residue, are introduced into Escherichia coli and then refined, has a specific covalent bond with an antibody when subject to UV irradiation, and thus the photomethionine-introduced protein G variant using the MRS variant can be utilized for producing a highly sensitive biochip, biosensor, or cell-capturing chip.