title: Fragmentation of multiply-charged intact protein ions using MALDI TOF-TOF mass spectrometry.
abstract: Top down proteomics in a TOF-TOF instrument was further explored by examining the fragmentation of multiply charged precursors ions generated by matrix-assisted laser desorption ionization. Evaluation of sample preparation conditions allowed selection of solvent/matrix conditions and sample deposition methods to produce sufficiently abundant doubly and triply charged precursor ions for subsequent CID experiments. As previously reported, preferential cleavage was observed at sites C-terminal to acidic residues and N-terminal to proline residues for all ions examined. An increase in nonpreferential fragmentation as well as additional low mass product ions was observed in the spectra from multiply charged precursor ions providing increased sequence coverage. This enhanced fragmentation from multiply charged precursor ions became increasingly important with increasing protein molecular weight and facilitates protein identification using database searching algorithms. The useable mass range for MALDI TOF-TOF analysis of intact proteins has been expanded to 18.2 kDa using this approach.
authors: Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
authors: Zhaoyang
authors: Z
authors: Liu
authors: Kevin L
authors: KL
authors: Schey
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001363:Awards and Prizes; D002417:Cattle; D029968:Escherichia coli Proteins / Q000032:analysis / Q000737:chemistry; D006736:Horses; D007782:Lactoglobulins / Q000032:analysis / Q000737:chemistry; D008894:Milk Proteins / Q000032:analysis / Q000737:chemistry; D008969:Molecular Sequence Data; D009211:Myoglobin / Q000032:analysis / Q000737:chemistry; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D040901:Proteomics / Q000295:instrumentation* / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013879:Thioredoxins / Q000032:analysis / Q000737:chemistry; D025801:Ubiquitin / Q000032:analysis / Q000737:chemistry
chemical_list: D029968:Escherichia coli Proteins; D007782:Lactoglobulins; D008894:Milk Proteins; D009211:Myoglobin; D011506:Proteins; D025801:Ubiquitin; D013879:Thioredoxins
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