title: Automatic identification of proteins with a MALDI-quadrupole ion trap mass spectrometer.
abstract: A matrix-assisted laser desorption/ionization (MALDI) ion trap mass spectrometer of new design is described. The instrument is based on a commercial Finnegan LCQ ion trap mass spectrometer to which we have added a MALDI ion source that incorporates a sample stage constructed from a compact disk and a new ion transmission interface. The ion interface contains a quadrupole ion guide installed between the skimmer and the octapoles of the original instrument configuration, allowing for operation in both MALDI and electrospray ionization modes. The instrument has femtomole sensitivity for peptides and is capable of collecting a large number of MALDI MS and MALDI MS/MS spectra within a short period of time. The MALDI source produces reproducible signals for 10(4)-10(5) laser pulses, enabling us to collect MS/MS spectra from all the discernible singly charged ions detected in a MS peptide map. We describe the different modes of the instrument operation and algorithms for data processing as applied to challenging protein identification problems.
authors.affiliation: Rockefeller University, New York, New York 10021, USA.
authors.forename: A N
authors.initials: AN
authors.lastname: Krutchinsky
authors.forename: M
authors.initials: M
authors.lastname: Kalkum
authors.forename: B T
authors.initials: BT
authors.lastname: Chait
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000032:analysis; D004268:DNA-Binding Proteins / Q000032:analysis; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis; D006801:Humans; D007477:Ions; D008565:Membrane Proteins / Q000032:analysis; D008969:Molecular Sequence Data; D009251:NADPH-Ferrihemoprotein Reductase / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D051381:Rats; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D029742:Caenorhabditis elegans Proteins; C091435:DDB1 protein, human; D004268:DNA-Binding Proteins; C490414:Ddb1 protein, rat; D018840:HSP70 Heat-Shock Proteins; D007477:Ions; D008565:Membrane Proteins; D011506:Proteins; C018551:glucose-regulated proteins; D009251:NADPH-Ferrihemoprotein Reductase