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C-terminal amino acid residue loss for deprotonated peptide ions containing glutamic acid, aspartic acid, or serine residues at the C-terminus.
J Mass Spectrom. 2006 Jul; 41(7):939-49.JM

Abstract

Deprotonated peptides containing C-terminal glutamic acid, aspartic acid, or serine residues were studied by sustained off-resonance irradiation collision-induced dissociation (SORI-CID) in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer with ion production by electrospray ionization (ESI). Additional studies were performed by post source decay (PSD) in a matrix-assisted laser desorption ionization/time-of-flight (MALDI/TOF) mass spectrometer. This work included both model peptides synthesized in our laboratory and bioactive peptides with more complex sequences. During SORI-CID and PSD, [M - H]- and [M - 2H]2- underwent an unusual cleavage corresponding to the elimination of the C-terminal residue. Two mechanisms are proposed to occur. They involve nucleophilic attack on the carbonyl carbon of the adjacent residue by either the carboxylate group of the C-terminus or the side chain carboxylate group of C-terminal glutamic acid and aspartic acid residues. To confirm the proposed mechanisms, AAAAAD was labelled by 18O specifically on the side chain of the aspartic acid residue. For peptides that contain multiple C-terminal glutamic acid residues, each of these residues can be sequentially eliminated from the deprotonated ions; a driving force may be the formation of a very stable pyroglutamatic acid neutral. For peptides with multiple aspartic acid residues at the C-terminus, aspartic acid residue loss is not sequential. For peptides with multiple serine residues at the C-terminus, C-terminal residue loss is sequential; however, abundant loss of other neutral molecules also occurs. In addition, the presence of basic residues (arginine or lysine) in the sequence has no effect on C-terminal residue elimination in the negative ion mode.

Authors+Show Affiliations

Department of Chemistry, The University of Alabama, Tuscaloosa, AL 35487, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

16810639

Citation

Li, Zhong, et al. "C-terminal Amino Acid Residue Loss for Deprotonated Peptide Ions Containing Glutamic Acid, Aspartic Acid, or Serine Residues at the C-terminus." Journal of Mass Spectrometry : JMS, vol. 41, no. 7, 2006, pp. 939-49.
Li Z, Yalcin T, Cassady CJ. C-terminal amino acid residue loss for deprotonated peptide ions containing glutamic acid, aspartic acid, or serine residues at the C-terminus. J Mass Spectrom. 2006;41(7):939-49.
Li, Z., Yalcin, T., & Cassady, C. J. (2006). C-terminal amino acid residue loss for deprotonated peptide ions containing glutamic acid, aspartic acid, or serine residues at the C-terminus. Journal of Mass Spectrometry : JMS, 41(7), 939-49.
Li Z, Yalcin T, Cassady CJ. C-terminal Amino Acid Residue Loss for Deprotonated Peptide Ions Containing Glutamic Acid, Aspartic Acid, or Serine Residues at the C-terminus. J Mass Spectrom. 2006;41(7):939-49. PubMed PMID: 16810639.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - C-terminal amino acid residue loss for deprotonated peptide ions containing glutamic acid, aspartic acid, or serine residues at the C-terminus. AU - Li,Zhong, AU - Yalcin,Talat, AU - Cassady,Carolyn J, PY - 2006/7/1/pubmed PY - 2007/8/19/medline PY - 2006/7/1/entrez SP - 939 EP - 49 JF - Journal of mass spectrometry : JMS JO - J Mass Spectrom VL - 41 IS - 7 N2 - Deprotonated peptides containing C-terminal glutamic acid, aspartic acid, or serine residues were studied by sustained off-resonance irradiation collision-induced dissociation (SORI-CID) in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer with ion production by electrospray ionization (ESI). Additional studies were performed by post source decay (PSD) in a matrix-assisted laser desorption ionization/time-of-flight (MALDI/TOF) mass spectrometer. This work included both model peptides synthesized in our laboratory and bioactive peptides with more complex sequences. During SORI-CID and PSD, [M - H]- and [M - 2H]2- underwent an unusual cleavage corresponding to the elimination of the C-terminal residue. Two mechanisms are proposed to occur. They involve nucleophilic attack on the carbonyl carbon of the adjacent residue by either the carboxylate group of the C-terminus or the side chain carboxylate group of C-terminal glutamic acid and aspartic acid residues. To confirm the proposed mechanisms, AAAAAD was labelled by 18O specifically on the side chain of the aspartic acid residue. For peptides that contain multiple C-terminal glutamic acid residues, each of these residues can be sequentially eliminated from the deprotonated ions; a driving force may be the formation of a very stable pyroglutamatic acid neutral. For peptides with multiple aspartic acid residues at the C-terminus, aspartic acid residue loss is not sequential. For peptides with multiple serine residues at the C-terminus, C-terminal residue loss is sequential; however, abundant loss of other neutral molecules also occurs. In addition, the presence of basic residues (arginine or lysine) in the sequence has no effect on C-terminal residue elimination in the negative ion mode. SN - 1076-5174 UR - https://www.unboundmedicine.com/medline/citation/16810639/C_terminal_amino_acid_residue_loss_for_deprotonated_peptide_ions_containing_glutamic_acid_aspartic_acid_or_serine_residues_at_the_C_terminus_ L2 - https://doi.org/10.1002/jms.1053 DB - PRIME DP - Unbound Medicine ER -