Methionyl trna synthetase for biosynthesis of photomethionine-labeled protein and method for preparing photoactive protein g variant using same

Abstract

Provided is a methionyl tRNA synthase (MRS) for the biosynthesis of a photomethionine-labeled protein and a method for preparing a photoactivatable protein G variant using same and, more particularly, to an MRS variant in which alanine at the position of 12is substituted with glycine, leucine at the position of 13by serine, tyrosine at the position of 260by phenylalanine, isoleucine at the position of 297by valine, and histidine at the position of 301by leucine from the N-terminal of the amino acid sequence of a wild-typemethionyl tRNA synthase. The MRS variant effectively confirms the biosynthesis of a photomethionine (pM)-labeled target protein and thus can be utilized for the biosynthesis of a pM-labeled target protein. In addition, a pM-introduced protein G variant, in which a plasmid encoding the MRS variant (MRS5m) and a PG-C3 plasmid, in which, in the third immunoglobulin G binding region of protein G, positions of 32, 35, and 40are substituted with a methionine (Met) residue and a position of 37by an arginine (Arg) residue, are introduced intoand then refined, has a specific covalent bond with an antibody when subject to UV irradiation, and thus the pM-introduced protein G variant using the MRS variant can be utilized for producing a highly sensitive biochip, biosensor, or cell-capturing chip.