- SEQUEST
Infobox Software
name = SEQUEST
caption =
author = Jimmy Eng and John Yates
developer =
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latest release version =
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genre = Protein identification
license = U.S. patents 6,017,693 and 5,538,897
website = http://fields.scripps.edu/sequest/SEQUEST is a
tandem mass spectrometry data analysis program used for protein identification.cite journal
author = Jimmy K. Eng, Ashley L. McCormack, and John R. Yates, III
title = An Approach to Correlate Tandem Mass Spectral Data of Peptides with Amino Acid Sequences in a Protein Database
journal = J Am Soc Mass Spectrom
volume = 5
pages = 976–989
year = 1994
doi = 10.1016/1044-0305(94)80016-2] Sequest identifies collections of tandem mass spectra to peptide sequences that have been generated from databases ofprotein sequences.Applications
This tool is most useful in the context of
proteomics . Starting with a complex mixture of proteins, this strategy typically employstrypsin to digest proteins. These peptides are separated byliquid chromatography en route to a tandem mass spectrometer. The mass spectrometer then isolates ions of a particular peptide, subjects them tocollision-induced dissociation , and records the produced fragments in a tandem mass spectrum. This process, repeated for several hours, will produce thousands of tandem mass spectra. Identifying such a data collection requires automation, and Sequest was the first software to fill that need.Sequest identifies each tandem mass spectrum individually. The software evaluates protein sequences from a database to compute the list of peptides that could result from each. The peptide's intact mass is known from the mass spectrum, and Sequest uses this information to determine the set of candidate peptides sequences that could meaningfully be compared to the spectrum by including only those which are near the mass of the observed peptide ion. For each candidate peptide, Sequest projects a theoretical tandem mass spectrum, and Sequest compares these theoretical spectra to the observed tandem mass spectrum by the use of
cross correlation . The candidate sequence with the best matching theoretical tandem mass spectrum is reported as the best identification for this spectrum.References
External links
* [http://www.sagenresearch.com/products.html Sequest Sorcerer]
* [http://www.proteomesoftware.com/Proteome_software_pro_interpreting.html Interpreting Tandem Mass Spectra]
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