Premium
Proteomics of gluten: mapping of the 1Bx7 glutenin subunit in Chinese Spring cultivar by matrix‐assisted laser desorption/ionization
Author(s) -
Alberghina Gaetano,
Cozzolino Rosaria,
Fisichella Salvatore,
Garozzo Domenico,
Savarino Anna
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2032
Subject(s) - glutenin , chemistry , protein subunit , cultivar , gluten , spring (device) , desorption , matrix (chemical analysis) , chromatography , proteomics , mass spectrometry , analytical chemistry (journal) , biochemistry , botany , organic chemistry , adsorption , gene , mechanical engineering , biology , engineering
The verification of the cDNA‐deduced sequence of the high molecular weight glutenin subunit 1Bx7 in Chinese Spring cultivar was achieved by direct matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) analysis of the tryptic fragments. The published sequence of the 1Bx7 subunit contains 5 Lys and 15 Arg residues but, due to the presence of three Arg–Pro bonds, which are generally resistant to cleavage by trypsin, or cleaved to a very limited extent by trypsin, 19 peptides can be predicted. The identification of the tryptic fragments was achieved by direct MALDI‐MS analysis by using three different matrices (DHB, SA and HCCA) in combination with the most compatible sample preparation procedures in order to obtain the maximum sequence coverage. MALDI analysis of the 1Bx7 tryptic digest resulted in the identification of the expected peptides and additional fragments arising from non‐specific cleavages; the fragments that were not detected are peptides with low mass (from 147.2 to 317.4), so we obtained a sequence coverage of 98.8%. The results reported here also indicated that the sequence of the 1Bx7 subunit from cv. Chinese Spring is different from the cDNA‐deduced sequence reported in the literature; in particular, a possible insertion of the hexapeptide QPGQGQ within the sequence Gln 630 ‐Tyr 725 was suggested. Finally, it is possible to rule out glycosylation of the 1Bx7 subunit, or any other post‐translational modification, to within the detection limits of the method. Copyright © 2005 John Wiley & Sons, Ltd.