title: De novo peptide sequencing using exhaustive enumeration of peptide composition.
abstract: We introduce the use of a peptide composition lookup table indexed by residual mass and number of amino acids for de novo sequencing of polypeptides. Polypeptides of 1600 Daltons (Da) or more can be sequenced effectively through exhaustive compositional analysis of MS/MS spectra obtained by unimolecular decomposition (without CID) in a MALDI TOF/TOF despite a fragment mass accuracy of 50 mDa. Peaks are referenced against the lookup table to obtain a complete profile of amino acid combinations, and combinations are assembled into series of increasing length. Concatenating the differences between successive entries in compositional series yields peptide sequences that can be scored and ranked according to signal intensity. While the current work involves measurements acquired on MALDI TOF-TOF, such general treatment of the data anticipates extension to other types of mass analyzers.
authors.affiliation: Laboratory of Cellular and Molecular Biophysics, NICHD, NIH, Bethesda, Maryland, USA.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Olson
authors.affiliation: Unit of Biologic Computation, OSD, NICHD, NIH, Bethesda, Maryland, USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Epstein
authors.affiliation: Laboratory of Cellular and Molecular Biophysics, NICHD, NIH, Bethesda, Maryland, USA. aly@helix.nih.gov.
authors.forename: Alfred L
authors.initials: AL
authors.lastname: Yergey
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D030562:Databases, Protein; D016247:Information Storage and Retrieval / Q000379:methods*; D008969:Molecular Sequence Data; D010449:Peptide Mapping / Q000379:methods*; D010455:Peptides / Q000737:chemistry*; D020539:Sequence Analysis, Protein / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D010455:Peptides