Method for verifying the primary structure of protein
AssigneeSun Jet Biotechnology Inc.
InventorsYeou Guang Tsay, Ya-Fen Chen
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Abstract
Disclosed herein is a method for verifying the primary structure of a protein through comparative analyses between ion clusters observed in mass spectra and a series of simulated ion clusters deduced from its putative chemical formula. The method comprises the steps of: preparing a protein sample for mass spectrometric analyses; collecting mass spectra of the protein sample; obtaining master ion cluster from a plurality of ion clusters in the mass spectra; producing a series of simulated ion clusters according to the chemical formula of the protein; finding the best fit for the master ion cluster among the series of simulated ion clusters; and verifying if said best-fit simulated ion cluster corresponds to the chemical formula of the protein.
Claims22
A method for verifying the primary structure of a protein comprising:
- obtaining a mass spectrum of a full-length protein;
- identifying from the mass spectrum a plurality of ion clusters with a mass corresponding to the full-length protein but with different charge states;
- calculating a master ion cluster from the plurality of ion clusters;
- and
- comparing the master ion cluster with a series of simulated ion clusters generated based on the chemical formula of the full-length protein with or without a modification, to find a best fitted simulated ion cluster;
- wherein the master ion cluster is calculated by a process comprising:
- summing up the intensities of the most abundant peak at (m/z)ma of each of the plurality of ion clusters, to obtain a starting summation;
- summing up the intensities of the next larger isotopic peak p(+1), with an m/z larger than the (m/z)ma according to an average isotope spacing, of each most abundant peak, to obtain a first right summation;
- and summing up the intensities of the next smaller isotopic peak p(−1), with an m/z smaller than the (m/z)ma according to the average isotope spacing, of each most abundant peak, to obtain a first left summation.
Dependencies are inferred from the claim text.