title: Method for quantitative proteomics research by using metal element chelated tags coupled with mass spectrometry.
abstract: The mass spectrometry-based methods with a stable isotope as the internal standard in quantitative proteomics have been developed quickly in recent years. But the use of some stable isotope reagents is limited by the relative high price and synthetic difficulties. We have developed a new method for quantitative proteomics research by using metal element chelated tags (MECT) coupled with mass spectrometry. The bicyclic anhydride diethylenetriamine-N,N,N',N' ',N' '-pentaacetic acid (DTPA) is covalently coupled to primary amines of peptides, and the ligand is then chelated to the rare earth metals Y and Tb. The tagged peptides are mixed and analyzed by LC-ESI-MS/MS. Peptides are quantified by measuring the relative signal intensities for the Y and Tb tag pairs in MS, which permits the quantitation of the original proteins generating the corresponding peptides. The protein is then identified by the corresponding peptide sequence from its MS/MS spectrum. The MECT method was evaluated by using standard proteins as model sample. The experimental results showed that metal chelate-tagged peptides chromatographically coeluted successfully during the reversed-phase LC analysis. The relative quantitation results were accurate for proteins using MECT. DTPA modification of the N-terminal of peptides promoted cleaner fragmentation (only y-series ions) in mass spectrometry and improved the confidence level of protein identification. The MECT strategy provides a simple, rapid, and economical alternative to current mass tagging technologies available.
authors.affiliation: Department of Genomics and Proteomics, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, China.
authors.forename: Huiling
authors.initials: H
authors.lastname: Liu
authors.forename: Yangjun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jinglan
authors.initials: J
authors.lastname: Wang
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Chunxi
authors.initials: C
authors.lastname: Zhou
authors.forename: Yun
authors.initials: Y
authors.lastname: Cai
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Qian
mesh_terms: D000595:Amino Acid Sequence; D002614:Chelating Agents / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods; D007768:Lactalbumin / Q000032:analysis; D007782:Lactoglobulins / Q000032:analysis; D008969:Molecular Sequence Data; D009211:Myoglobin / Q000032:analysis; D004369:Pentetic Acid / Q000737:chemistry*; D011506:Proteins / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D012710:Serum Albumin, Bovine / Q000032:analysis; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013725:Terbium / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D007782:Lactoglobulins; D009211:Myoglobin; D011506:Proteins; C064259:beta-lactoglobin W; D013725:Terbium; D012710:Serum Albumin, Bovine; D004369:Pentetic Acid; D007768:Lactalbumin; D015018:Ytterbium