Premium
Structural studies of the allelic wheat glutenin subunits 1Bx7 and 1Bx20 by matrix‐assisted laser desorption/ionization mass spectrometry and high‐performance liquid chromatography/electrospray ionization mass spectrometry
Author(s) -
Cunsolo Vincenzo,
Foti Salvatore,
Saletti Rosaria,
Gilbert Simon,
Tatham Arthur S.,
Shewry Peter R.
Publication year - 2004
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.558
Subject(s) - chemistry , mass spectrometry , chromatography , protein mass spectrometry , electrospray ionization , sample preparation in mass spectrometry , glutenin , time of flight mass spectrometry , high performance liquid chromatography , mass spectrum , matrix assisted laser desorption/ionization , analytical chemistry (journal) , ionization , desorption , protein subunit , biochemistry , organic chemistry , gene , adsorption , ion
Structural studies of the high molecular mass (HMM) glutenin subunits 1Bx7 (from cvs Hereward and Galatea) and 1Bx20 (from cv. Bidi17) of bread wheat were conducted using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and reversed‐phase high‐performance liquid chromatography/electrospray ionization mass spectrometry (RP‐HPLC/ESI‐MS). For all three proteins, MALDI‐TOFMS analysis showed that the isolated fractions contained a second component with a mass about 650 Da lower than the major component. The testing and correction of the gene‐derived amino acid sequences of the three proteins were performed by direct MALDI‐TOFMS analysis of their tryptic peptide mixture. Analysis of the digest was performed by recording several MALDI mass spectra of the mixture at low, medium and high mass ranges, optimizing the matrix and the acquisition parameters for each mass range. Complementary data were obtained by RP‐HPLC/ESI‐MS analysis of the tryptic digest. This resulted in coverage of about 98% of the sequences. In contrast to the gene‐derived data, the results obtained demonstrate the insertion of the sequence QPGQGQ between Trp 716 and Gln 717 of subunit 1Bx7 (cv. Galatea) and a possible single amino acid substitution within the T20 peptide of subunit 1Bx20. Moreover, the mass spectrometric data demonstrated that the lower mass components present in all the fractions correspond to the major components but lack about six amino acid residues, which are probably lost from the protein C‐terminus. Finally, the results obtained provide evidence for the lack of glycosylation or other post‐translational modifications of these subunits. Copyright © 2004 John Wiley & Sons, Ltd.