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Efficient sequence analysis of the six gene products (7‐74 kDA) from the escherichia coli thiamin biosynthetic operon by tandem high‐resolution mass spectrometry
Author(s) -
Kelleher Neil L.,
Taylor Sean V.,
Grannis David,
Kinsland Cynthia,
Chiu HsiuJu,
Begley Tadhg P.,
Mclafferty Fred W.
Publication year - 1998
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560070815
Subject(s) - operon , escherichia coli , chemistry , tandem mass spectrometry , mass spectrometry , sequence analysis , sequence (biology) , gene , resolution (logic) , biochemistry , tandem mass tag , peptide sequence , tandem , chromatography , biology , proteomics , materials science , quantitative proteomics , artificial intelligence , composite material , computer science
The 10 5 resolving power and MS/MS capabilities of Fourier‐transform mass spectrometry provide electrospray ionization mass spectra containing > 100 molecular and fragment ion mass values of high accuracy. Applying these spectra to the detection and localization of errors and modifications in the DNA‐derived sequences of proteins is illustrated with the thiCEFSGH thiamin biosynthesis operon from Escherichia coli . Direct fragmentation of the multiply‐charged intact protein ions produces large fragment ions covering the entire sequence; further dissociation of these fragment ions provides information on their sequences. For ThiE (23 kDa), the entire sequence was verified in a single spectrum with an accurate (0.3 Da) molecular weight ( M r ) value, with confirmation from MS/MS fragment masses. Those for ThiH (46 kDa) showed that the M r value (1 Da error) represented the protein without the start Met residue. For ThiF (27 kDa), MS/MS localized a sequence discrepancy to a 34 residue peptide. The first 107 residues of ThiC (74 kDa) were shown to be correct, with C‐terminal heterogeneity indicated. For ThiG (predicted M r = 34 kDa), ESI/FTMS showed two components of 7,310.74 (ThiS) and 26,896.5 Da (ThiG); MS/MS uncovered three reading frame errors and a stop codon for the first protein. MS/MS ions are consistent with 68 fragments predicted by the corrected ThiS/ThiG DNA sequences.