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Differentiation of three pairs of Boc-beta,gamma- and gamma,beta-hybrid peptides by electrospray ionization tandem mass spectrometry.
J Mass Spectrom. 2008 Sep; 43(9):1201-14.JM

Abstract

A new series of Boc-N-beta(3), gamma(4)-/gamma(4), beta(3)-isomeric hybrid peptides (containing repeats of beta(3)-Caa and gamma(4)-Caa's, Caa = C-linked carbo beta(3)-/gamma(4)-amino acids derived from D-xylose) have been differentiated by both positive and negative ion electrospray ionization (ESI) ion-trap and high resolution quadrupole time-of-flight/tandem mass spectrometry (Q-TOF MS/MS). MS(n) of protonated isomeric peptides and [M+H-Boc+H](+) produce characteristic fragmentation involving the peptide backbone, the Boc-group, and the side chain. The positional isomers are differentiated from one another by the presence of y(n)(+), b(n)(+), and other fragment ions of different m/z values. It is observed that the peptides with beta-Caa at the N-terminus produce extensive fragmentation, whereas gamma-Caa gave rise to much less fragmentation. Peptides with gamma-Caa at the N-terminus lose NH(3), whereas this process is absent for the carbopeptides with beta-Caa at the N-terminus. Two pairs of dipeptide diastereomers are clearly differentiated by the collision-induced dissociation (CID) of their protonated molecules. The loss of 2-methylprop-1-ene is more pronounced for Boc-NH-(R)-beta-Caa-(R)-gamma-Caa-OCH(3) (6) and Boc-NH-(R)-gamma-Caa-(R)-beta-Caa-OCH(3) (12), whereas it is insignificant or totally absent for its protonated diastereomeric pair Boc-NH-(S)-beta-Caa-(S)-gamma-Caa-OCH(3) (1) and Boc-NH-(S)-gamma-Caa-(S)-beta-Caa-OCH(3) (7). Further, ESI negative ion tandem mass spectrometry has also been found to be useful for differentiating these isomeric peptide acids.

Authors+Show Affiliations

National Centre for Mass Spectrometry, Indian Institute of Chemical Technology, Hyderabad 500 007, India.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18320536

Citation

Ramesh, V, et al. "Differentiation of Three Pairs of Boc-beta,gamma- and Gamma,beta-hybrid Peptides By Electrospray Ionization Tandem Mass Spectrometry." Journal of Mass Spectrometry : JMS, vol. 43, no. 9, 2008, pp. 1201-14.
Ramesh V, Srinivas R, Sharma GV, et al. Differentiation of three pairs of Boc-beta,gamma- and gamma,beta-hybrid peptides by electrospray ionization tandem mass spectrometry. J Mass Spectrom. 2008;43(9):1201-14.
Ramesh, V., Srinivas, R., Sharma, G. V., Jayaprakash, P., & Kunwar, A. C. (2008). Differentiation of three pairs of Boc-beta,gamma- and gamma,beta-hybrid peptides by electrospray ionization tandem mass spectrometry. Journal of Mass Spectrometry : JMS, 43(9), 1201-14. https://doi.org/10.1002/jms.1393
Ramesh V, et al. Differentiation of Three Pairs of Boc-beta,gamma- and Gamma,beta-hybrid Peptides By Electrospray Ionization Tandem Mass Spectrometry. J Mass Spectrom. 2008;43(9):1201-14. PubMed PMID: 18320536.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differentiation of three pairs of Boc-beta,gamma- and gamma,beta-hybrid peptides by electrospray ionization tandem mass spectrometry. AU - Ramesh,V, AU - Srinivas,R, AU - Sharma,G V M, AU - Jayaprakash,P, AU - Kunwar,A C, PY - 2008/3/6/pubmed PY - 2008/10/11/medline PY - 2008/3/6/entrez SP - 1201 EP - 14 JF - Journal of mass spectrometry : JMS JO - J Mass Spectrom VL - 43 IS - 9 N2 - A new series of Boc-N-beta(3), gamma(4)-/gamma(4), beta(3)-isomeric hybrid peptides (containing repeats of beta(3)-Caa and gamma(4)-Caa's, Caa = C-linked carbo beta(3)-/gamma(4)-amino acids derived from D-xylose) have been differentiated by both positive and negative ion electrospray ionization (ESI) ion-trap and high resolution quadrupole time-of-flight/tandem mass spectrometry (Q-TOF MS/MS). MS(n) of protonated isomeric peptides and [M+H-Boc+H](+) produce characteristic fragmentation involving the peptide backbone, the Boc-group, and the side chain. The positional isomers are differentiated from one another by the presence of y(n)(+), b(n)(+), and other fragment ions of different m/z values. It is observed that the peptides with beta-Caa at the N-terminus produce extensive fragmentation, whereas gamma-Caa gave rise to much less fragmentation. Peptides with gamma-Caa at the N-terminus lose NH(3), whereas this process is absent for the carbopeptides with beta-Caa at the N-terminus. Two pairs of dipeptide diastereomers are clearly differentiated by the collision-induced dissociation (CID) of their protonated molecules. The loss of 2-methylprop-1-ene is more pronounced for Boc-NH-(R)-beta-Caa-(R)-gamma-Caa-OCH(3) (6) and Boc-NH-(R)-gamma-Caa-(R)-beta-Caa-OCH(3) (12), whereas it is insignificant or totally absent for its protonated diastereomeric pair Boc-NH-(S)-beta-Caa-(S)-gamma-Caa-OCH(3) (1) and Boc-NH-(S)-gamma-Caa-(S)-beta-Caa-OCH(3) (7). Further, ESI negative ion tandem mass spectrometry has also been found to be useful for differentiating these isomeric peptide acids. SN - 1076-5174 UR - https://www.unboundmedicine.com/medline/citation/18320536/Differentiation_of_three_pairs_of_Boc_betagamma__and_gammabeta_hybrid_peptides_by_electrospray_ionization_tandem_mass_spectrometry_ DB - PRIME DP - Unbound Medicine ER -