Tandem mass spectrometric analysis of (13)C-containing ions from a mixture of homologous peptides differing by one mass unit at a residue.
Tandem mass spectrometry of a mixture of two peptides that differ from each other by a single mass unit due to mutation is presented. The mutant beta-globin of hemoglobin Hoshida is present along with the normal counterpart, and the amino acid substitution of glutamine for glutamic acid is located within tryptic peptide T5 of M(r) 2057. 9. The mass of the mutated peptide is 1 u lower. In the isotopic cluster for the doubly charged ion of the peptide T5, the resolved ion with mass of 1030.0 represents the normal peptide with 93 (12)C atoms and the mutated one with 92 (12)C and one (13)C atoms. Collision-induced dissociation (CID) of this composite ion identified the mutation by presenting a key fragment derived from the (12)C-only mutant peptide, as reported in a previous study. Similarly, when an ion containing multiple (13)C atoms was selected as a precursor for CID, the mutation could be identified, even in large fragments, by a marked change in the shape of the isotopic cluster for the consecutive product ions. This study demonstrates the merit of selecting a resolved ion rather than the whole isotopic cluster as a precursor in the CID measurements of large peptides or proteins for characterizing heterozygous mutations.
Wada
Y
Y
Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Murodo-cho, Izumi, Osaka 594-1101, Japan. j61638@center.osaka-u.ac.jp
Hisada
M
M
Kaneko
R
R
Naoki
H
H
Matsuo
T
T
D000595:Amino Acid Sequence; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D010455:Peptides / Q000737:chemistry* / Q000235:genetics; D016339:Spectrometry, Mass, Fast Atom Bombardment
D010455:Peptides