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

摘要

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 12^th is substituted with glycine, leucine at the position of 13^th by serine, tyrosine at the position of 260^th by phenylalanine, isoleucine at the position of 297^th by valine, and histidine at the position of 301^st by leucine from the N-terminal of the amino acid sequence of a wild-type Escherichia coli methionyl 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^nd, 35^th, and 40^th are substituted with a methionine (Met) residue and a position of 37^th 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 pM-introduced protein G variant using the MRS variant can be utilized for producing a highly sensitive biochip, biosensor, or cell-capturing chip.