The present invention relates to a method for diagnosis of bile duct cancer, using methionyl-tRNA synthetase (MRS) in bile duct cells of a latent patient.

Reagents and methods for the digital analysis of proteins or peptides are provided. Specifically provided herein are proteins for identifying the N-terminal amino acid or N-terminal phosphorylated amino acid of a polypeptide. Also, an enzyme for use in the cleavage step of the Edman degradation reaction and a method for using this enzyme are described.

Reagents and methods for the digital analysis of proteins or peptides are provided. Specifically provided herein are proteins for identifying the N-terminal amino acid or N-terminal phosphorylated amino acid of a polypeptide. Also, an enzyme for use in the cleavage step of the Edman degradation reaction and a method for using this enzyme are described.

Reagents and methods for the digital analysis of proteins or peptides are provided. Specifically provided herein are proteins for identifying the N-terminal amino acid or N-terminal phosphorylated amino acid of a polypeptide. Also, an enzyme for use in the cleavage step of the Edman degradation reaction and a method for using this enzyme are described.

The present invention relates to a method for diagnosis of bile duct cancer, using methionyl-tRNA synthetase (MRS) in bile duct cells of a latent patient.

Provided are compositions comprising newly identified protein fragments of aminoacyl-tRNA synthetases, polynucleotides that encode them and complements thereof, related agents, and methods of use thereof in diagnostic, drug discovery, research, and therapeutic applications.

The present invention relates to the development of and use of genetically modified human differentiated cells coupled with xenotransplantation into animal models to identify injury and disease-specific RNA and/or protein biomarkers. Specifically, the present invention encompasses two complementary methods for biomarker discovery that enable the direct and selective labelling, isolation, and analysis of human-specific RNA and/or proteins from xenotransplantation (or chimeric) animal models. Both methods involve the treatment of animal models with an RNA analog and/or amino acid analog that enables the specific isolation and quantification of human RNAs and/or proteins for the identification of novel human biomarkers for a large array of human injuries and diseases.

Reagents and methods for the digital analysis of proteins or peptides are provided. Specifically provided herein are proteins for identifying the N-terminal amino acid or N-terminal phosphorylated amino acid of a polypeptide. Also, an enzyme for use in the cleavage step of the Edman degradation reaction and a method for using this enzyme are described.

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.sup.th is substituted with glycine, leucine at the position of 13.sup.th by serine, tyrosine at the position of 260.sup.th by phenylalanine, isoleucine at the position of 297.sup.th by valine, and histidine at the position of 301.sup.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.sup.nd, 35.sup.th, and 40.sup.th are substituted with a methionine (Met) residue and a position of 37.sup.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.

Provided are compositions comprising newly identified protein fragments of aminoacyl-tRNA synthetases, polynucleotides that encode them and complements thereof, related agents, and methods of use thereof in diagnostic, drug discovery, research, and therapeutic applications.