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Electrospray ionization tandem mass spectrometric study on the effect of N-terminal beta- and gamma-carbo amino acids on fragmentation of GABA-hybrid peptides.
Rapid Commun Mass Spectrom. 2008 Nov; 22(21):3339-52.RC

Abstract

The fragmentations of protonated and deprotonated ions of a new class of N-blocked hybrid Boc-carbopeptides containing repeats of gamma-Caa/gammaAbu- and beta-Caa/gammaAbu- (Caa==C-linked carbo gamma(4)-/beta(3)- amino acids derived from D-xylose, gammaAbu = gamma-aminobutyric acid) have been studied using electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS). MS/MS of a pair of these protonated diastereomers produces distinct fragmentation of the Boc group. The formation of [M + H-56](+) corresponding to loss of isobutylene is more pronounced for Boc-NH-(R)-gamma-Caa-gammaAbu-OH (2) whereas it is of low abundance for Boc-NH-(S)-gamma-Caa-gammaAbu--OH (1). Similarly, MS(2) of [M--H](-) of 2 produces an abundant [M--H--C(CH(3))(3)OH--CO(2)](-) ion, which is absent for its diastereomeric isomer 1. From this, it can be suggested that MS/MS of N-blocked Boc-protected carbopeptides may be helpful in distinguishing the stereochemistry of the N-terminus Caa. MS(3) of [M + H-Boc + H](+) ions of peptides with a gamma-amino acid (gamma-Caa/gammaAbu) at the N-terminus produces only abundant y(n) (+) ions. On the other hand, characteristic fragmentations involving the peptide backbone (b(n) (+) and y(n) (+)) and the side chain are seen when beta-Caa is at the N-terminus of the peptides. MS(3) of the [M--H--C(CH(3))(3)OH](-) ion of peptides containing gamma-Caa/gammaAbu at the N-terminus gave y(n) (-) and [M--H--C(CH(3))(3)OH--CO(2)](-) ions, whereas the presence of beta-Caa at the N-terminus yielded predominantly [M--H--C(CH(3))(3)OH--HNCO](-). Thus, on the basis of our previous study and that presented here we propose that the fragmentation of these hybrid carbopeptides is highly influenced by the type of carbo amino acid present at the N-terminus.

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

Language

eng

PubMed ID

18837002

Citation

Ramesh, V, et al. "Electrospray Ionization Tandem Mass Spectrometric Study On the Effect of N-terminal Beta- and Gamma-carbo Amino Acids On Fragmentation of GABA-hybrid Peptides." Rapid Communications in Mass Spectrometry : RCM, vol. 22, no. 21, 2008, pp. 3339-52.
Ramesh V, Ramesh M, Srinivas R, et al. Electrospray ionization tandem mass spectrometric study on the effect of N-terminal beta- and gamma-carbo amino acids on fragmentation of GABA-hybrid peptides. Rapid Commun Mass Spectrom. 2008;22(21):3339-52.
Ramesh, V., Ramesh, M., Srinivas, R., Sharma, G. V., & Jayaprakash, P. (2008). Electrospray ionization tandem mass spectrometric study on the effect of N-terminal beta- and gamma-carbo amino acids on fragmentation of GABA-hybrid peptides. Rapid Communications in Mass Spectrometry : RCM, 22(21), 3339-52. https://doi.org/10.1002/rcm.3743
Ramesh V, et al. Electrospray Ionization Tandem Mass Spectrometric Study On the Effect of N-terminal Beta- and Gamma-carbo Amino Acids On Fragmentation of GABA-hybrid Peptides. Rapid Commun Mass Spectrom. 2008;22(21):3339-52. PubMed PMID: 18837002.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Electrospray ionization tandem mass spectrometric study on the effect of N-terminal beta- and gamma-carbo amino acids on fragmentation of GABA-hybrid peptides. AU - Ramesh,V, AU - Ramesh,M, AU - Srinivas,R, AU - Sharma,G V M, AU - Jayaprakash,P, PY - 2008/10/7/pubmed PY - 2008/12/19/medline PY - 2008/10/7/entrez SP - 3339 EP - 52 JF - Rapid communications in mass spectrometry : RCM JO - Rapid Commun Mass Spectrom VL - 22 IS - 21 N2 - The fragmentations of protonated and deprotonated ions of a new class of N-blocked hybrid Boc-carbopeptides containing repeats of gamma-Caa/gammaAbu- and beta-Caa/gammaAbu- (Caa==C-linked carbo gamma(4)-/beta(3)- amino acids derived from D-xylose, gammaAbu = gamma-aminobutyric acid) have been studied using electrospray ionization (ESI) ion-trap tandem mass spectrometry (MS/MS). MS/MS of a pair of these protonated diastereomers produces distinct fragmentation of the Boc group. The formation of [M + H-56](+) corresponding to loss of isobutylene is more pronounced for Boc-NH-(R)-gamma-Caa-gammaAbu-OH (2) whereas it is of low abundance for Boc-NH-(S)-gamma-Caa-gammaAbu--OH (1). Similarly, MS(2) of [M--H](-) of 2 produces an abundant [M--H--C(CH(3))(3)OH--CO(2)](-) ion, which is absent for its diastereomeric isomer 1. From this, it can be suggested that MS/MS of N-blocked Boc-protected carbopeptides may be helpful in distinguishing the stereochemistry of the N-terminus Caa. MS(3) of [M + H-Boc + H](+) ions of peptides with a gamma-amino acid (gamma-Caa/gammaAbu) at the N-terminus produces only abundant y(n) (+) ions. On the other hand, characteristic fragmentations involving the peptide backbone (b(n) (+) and y(n) (+)) and the side chain are seen when beta-Caa is at the N-terminus of the peptides. MS(3) of the [M--H--C(CH(3))(3)OH](-) ion of peptides containing gamma-Caa/gammaAbu at the N-terminus gave y(n) (-) and [M--H--C(CH(3))(3)OH--CO(2)](-) ions, whereas the presence of beta-Caa at the N-terminus yielded predominantly [M--H--C(CH(3))(3)OH--HNCO](-). Thus, on the basis of our previous study and that presented here we propose that the fragmentation of these hybrid carbopeptides is highly influenced by the type of carbo amino acid present at the N-terminus. SN - 0951-4198 UR - https://www.unboundmedicine.com/medline/citation/18837002/Electrospray_ionization_tandem_mass_spectrometric_study_on_the_effect_of_N_terminal_beta__and_gamma_carbo_amino_acids_on_fragmentation_of_GABA_hybrid_peptides_ L2 - https://doi.org/10.1002/rcm.3743 DB - PRIME DP - Unbound Medicine ER -