Fragmentation of protonated oligoalanines: Amide bond cleavage and beyond

Articles

Abstract

The fragmentation reactions of the singly-protonated oligoalanines trialanine to hexaalanine have been studied using energy-resolved mass spectrometry in MS2 and MS3 experiments. The primary fragmentation reactions are rationalized in terms of the bx-yz pathway of amide bond cleavage which results in formation of a proton-bound complex of an oxazolone and a peptide/amino acid; on decomposition of this complex the species of higher proton affinity preferentially retains the proton. For protonated pentaalanine and protonated hexaalanine the major primary fragmentation reaction involves cleavage of the C-terminal amide bond to form the appropriate b ion. The lower mass b ions originate largely, if not completely, by further fragmentation of the initially formed b ion. MS3 energy-resolved experiments clearly show the fragmentation sequence bn → bn−1 → bn−2. A more minor pathway for the alanines involves the sequence bn → an → bn−1 → bn−2. The a5 ion formed from hexaalanine loses, in part, NH3 to begin the sequence of fragmentation reactions a5 → a*5 → a*4 → a*3 where a*n = an−NH3. The a*3 ion also is formed from the b3 ion by the sequence b3 → a3 → a*3 with the final step being sufficiently facile that the a3 ion is not observed with significant intensity in CID mass spectra. A cyclic structure is proposed for the a*3 ion.

References

  1. 1.
    Whitehouse, C. M.; Dreyer, R. N.; Yamashita, M.; Fenn, J. B. Electrospray Interface for Liquid Chromatographs and Mass Spectrometers. Anal. Chem. 1985, 57, 675.CrossRefGoogle Scholar
  2. 2.
    Electrospray Ionization Mass Spectrometry. Fundamentals, Instrumentation, and Applications; Cole, R. B., Ed.; Wiley: New York, 1997.Google Scholar
  3. 3.
    Applied Electrospray Mass Spectrometry; Pramanik, B. N.; Ganguly, A. K.; Gross, M. L., Eds.; Marcel Dekker: New York, 2002.Google Scholar
  4. 4.
    Karas, M.; Hillenkamp, F. Laser Desorption Ionization of Proteins with Molecular Masses Exceeding 1000 Daltons. Anal. Chem. 1988, 60, 2299.CrossRefGoogle Scholar
  5. 5.
    Beavis, R. C.; Chait, B. T. Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry of Proteins. Methods Enzymol. 1996, 270, 519.CrossRefGoogle Scholar
  6. 6.
    Tandem Mass Spectrometry; McLafferty, F. W. Ed.; Wiley: New York, 1983.Google Scholar
  7. 7.
    Busch, K. L.; Glish, G. L.; McLuckey, S. A. Mass Spectrometry/Mass Spectrometry: Techniques and Applications of Tandem Mass Spectrometry; VCH: New York, 1988.Google Scholar
  8. 8.
    Roepstorff, P.; Fohlman, J. Proposal for a Common Nomenclature for Sequence Ions in Mass Spectra of Peptides. Biomed. Mass Spectrom. 1984, 11, 601.CrossRefGoogle Scholar
  9. 9.
    Biemann, K. Contributions of Mass Spectrometry to Peptide and Protein Structure. Biomed. Env. Mass Spectrom. 1988, 16, 99.CrossRefGoogle Scholar
  10. 10.
    Biemann, K. Sequencing of Peptides by Tandem Mass Spectrometry and High-Energy Collision-Induced Dissociation. Methods Enzymol. 1990, 193, 455.CrossRefGoogle Scholar
  11. 11.
    Papayannopoulos, I. A. The Interpretation of Collision-Induced Dissociation Tandem Mass Spectra of Peptides. Mass Spectrom. Rev. 1995, 14, 49.CrossRefGoogle Scholar
  12. 12.
    Mueller, D. R.; Eckersley, M.; Richter, W. Hydrogen Transfer Reactions in the Formation of “Y+2” Sequence Ions from Protonated Peptides. Org. Mass Spectrom. 1988, 23, 217.CrossRefGoogle Scholar
  13. 13.
    Cordero, M. M.; Houser, J. J.; Wesdemiotis, C. The Neutral Products Formed During Backbone Fragmentation of Protonated Peptides in Tandem Mass Spectrometry. Anal. Chem. 1993, 65, 1594.CrossRefGoogle Scholar
  14. 14.
    Yalcin, T.; Khouw, C.; Csizmadia, I. G.; Peterson, M. R.; Harrison, A. G. Why are B Ions Stable Species in Peptide Mass Spectra?. J. Am. Soc. Mass Spectrom. 1995, 6, 1165.CrossRefGoogle Scholar
  15. 15.
    Yalcin, T.; Csizmadia, I. G.; Peterson, M. R.; Harrison, A. G. The Structures and Fragmentation of Bn (n≥3) Ions in Peptide Mass Spectra. J. Am. Soc. Mass Spectrom. 1996, 7, 293.CrossRefGoogle Scholar
  16. 16.
    Nold, M. J.; Wesdemiotis, C.; Yalcin, T.; Harrison, A. G. Amide Bond Dissociation in Protonated Peptides. Structures of the N-Terminal Ionic and Neutral Fragments. Int. J. Mass Spectrom. Ion Processes. 1997, 164, 137.CrossRefGoogle Scholar
  17. 17.
    Paizs, B.; Lendvay, G.; Vékey, K.; Suhai, S. Formation of b2+ Ions from Protonated Peptides. An ab Initio Study. Rapid Commun. Mass Spectrom. 1999, 13, 525.CrossRefGoogle Scholar
  18. 18.
    Harrison, A. G.; Csizmadia, I. G.; Tang, T.-H. Structures and Fragmentation of b2 Ions in Peptide Mass Spectra. J. Am. Soc. Mass Spectrom. 2000, 11, 427.CrossRefGoogle Scholar
  19. 19.
    Rodriquez, C. F.; Shoeib, T.; Chu, I. K.; Siu, K. W. M.; Hopkinson, A. C. Comparison Between Protonation, Lithiation, and Argentination of 5-Oxazolones. A Study of a Key Intermediate in Gas-Phase Peptide Sequencing. J. Phys. Chem. A 2000, 104, 5355.Google Scholar
  20. 20.
    Farrugia, J. M.; Taverner, T.; O’Hair, R. A. J. Side-Chain Involvement in the Fragmentation Reactions of the Protonated Methyl Esters of Histidine and Its Peptides. Int. J. Mass Spectrom. 2001, 209, 99.CrossRefGoogle Scholar
  21. 21.
    Farrugia, J. M.; O’Hair, R. A. J.; Reid, G. E. Do All b2 Ions Have Oxazolone Structures? Mass Spectrometry and ab Initio Studies on Protonated N-Acyl Amino Acid Methyl Ester Model Systems. Int. J. Mass Spectrom 2001, 210/211, 71.CrossRefGoogle Scholar
  22. 22.
    Ambihapathy, K.; Yalcin, T.; Leung, H.-W.; Harrison, A. G. Pathways to Immonium Ions in the Fragmentation of Protonated Peptides. J. Mass Spectrom 1997, 32, 209.CrossRefGoogle Scholar
  23. 23.
    Aribi, E. L. H.; Rodriquez, C. F.; Almeida, D. R. P.; Ling, Y.; Mak, W. W.-N.; Hopkinson, A. C.; Siu, K. W. M. Elucidation of Fragmentation Mechanisms of Protonated Peptide Ions and Their Products: A Case Study on Glycylglycylglycine Using Density Functional Theory and Threshold Collision-Induced Dissociation. J. Am. Chem. Soc 2003, 125, 9229.CrossRefGoogle Scholar
  24. 24.
    Yeh, R. W.; Grimsley, J. M.; Bursey, M. M. Collisionally Induced Fragmentation of Protonated Oligoalanines and Oligoglycines. Biol. Mass Spectrom. 1991, 20, 443.CrossRefGoogle Scholar
  25. 25.
    Schwartz, B. L.; Bursey, M. M. Some Proline Substituent Effects in the Tandem Mass Spectrum of Protonated Pentaalanine. Biol. Mass Spectrom. 1992, 21, 92.CrossRefGoogle Scholar
  26. 26.
    Laskin, J.; Denisov, E.; Futrell, J. Comparative Study of Collision-induced and Surface-Induced Dissociation. 2. Fragmentation of Small Alanine-Containing Peptides in FT-ICR MS. J. Phys. Chem. B 2001, 105, 1895.CrossRefGoogle Scholar
  27. 27.
    Laskin, J.; Denisov, E.; Futrell, J. Fragmentation Energetics of Small Peptides from Multiple-Collision Activation and Surface-Induced Dissociation in FT-ICR MS. Int. J. Mass Spectrom. 2002, 219, 189.CrossRefGoogle Scholar
  28. 28.
    Laskin, J.; Futrell, J. Surface-Induced Dissociation of Peptides: Kinetics and Dynamics. J. Am. Soc. Mass Spectrom. 2003, 14, 1340.CrossRefGoogle Scholar
  29. 29.
    Paizs, B.; Suhai, S. Towards Understanding the Tandem Mass Spectra of Protonated Oligopeptides 1: Mechanism of Amide Bond Cleavage. J. Am. Soc. Mass Spectrom. 2004, 15, 103.CrossRefGoogle Scholar
  30. 30.
    Harrison, A. G. Energy-Resolved Mass Spectrometry. A Comparison of Quadrupole Cell and Cone Voltage Collision-Induced Dissociation. Rapid Commun. Mass Spectrom. 1999, 13, 1663.CrossRefGoogle Scholar
  31. 31.
    van Dongen, W. D.; van Wijk, J. I. T.; Green, B. M.; Heerma, W.; Haverkamp, J. Comparison Between Collision Induced Dissociation of Electrosprayed Protonated Peptides in the Up-Front Region and in a Low-Energy Collision Cell. Rapid Commun. Mass Spectrom 1999, 13, 1712.CrossRefGoogle Scholar
  32. 32.
    Harrison, A. G. Fragmentation Reactions of Alkylphenyl Ammonium Ions. J. Mass Spectrom. 1999, 34, 1253.CrossRefGoogle Scholar
  33. 33.
    Makowiecki, J.; Tolonen, A.; Uusitalo, J.; Jalonen, J. Cone Voltage and Collision Cell Collision-Induced Dissociation of Triphenylethylenes of Pharmaceutical Interest. Rapid Commun. Mass Spectrom. 2001, 15, 1506.CrossRefGoogle Scholar
  34. 34.
    Buré, C.; Lange, C. Comparison of Dissociation of Ions in an Electrospray Source or a Collision Cell in Tandem Mass Spectrometry. Curr. Org. Chem. 2003, 7, 1613.CrossRefGoogle Scholar
  35. 35.
    McLuckey, S. A.; Cooks, R. G. Angle- and Energy-Resolved Fragmentation from Tandem Mass Spectrometry. In Tandem Mass Spectrometry; McLafferty, F. W., Ed.; Wiley: New York, 1983; p 203.Google Scholar
  36. 36.
    Smith, R. D.; Loo, J. A.; Barinaga, C. J.; Edmonds, C. G.; Udseth, H. R. Collisional Activation and Collision-Activated Dissociation of Large Multiply Charged Polypeptides and Proteins Produced by Electrospray Ionization. J. Am. Soc. Mass Spectrom. 1990, 1, 53.CrossRefGoogle Scholar
  37. 37.
    Chen, H.; Tabei, K.; Siegel, M. M. Biopolymer Sequencing Using a Triple Quadrupole Mass Spectrometer in the ESI Nozzle-Skimmer/Precursor Ion MS/MS Mode. J. Am. Soc. Mass Spectrom. 2001, 12, 846.CrossRefGoogle Scholar
  38. 38.
    Paizs, B.; Suhai, S. Combined Quantum Chemical and RRKM Modeling of the Main Fragmentation Pathways of Protonated GGG. II. Formation of b2, y1 and y2 Ions. Rapid Commun. Mass Spectrom. 2002, 16, 375.CrossRefGoogle Scholar
  39. 39.
    Paizs, B.; Suhai, S. Towards Understanding Some Ion Intensity Relationships for the Tandem Mass Spectra of Protonated Peptides. Rapid Commun. Mass Spectrom. 2002, 16, 1699.CrossRefGoogle Scholar
  40. 40.
    Paizs, B.; Suhai, S.; Harrison, A. G. Experimental and Theoretical Investigation of the Main Fragmentation Pathways of Protonated H-Gly-Gly-Sar-OH and H-Gly-Sar-Sar-OH. J. Am. Soc. Mass Spectrom. 2003, 14, 1454.CrossRefGoogle Scholar
  41. 41.
    Paizs, B.; Suhai, S. Fragmentation Pathways of Protonated Peptides. Mass Spectrom. Rev., in press.Google Scholar
  42. 42.
    Fang, D.-C.; Yalcin, T.; Tang, T.-H.; Fu, X.-Y.; Harrison, A. G.; Csizmadia, I. G. Electron Distribution in Cationic Fragments Generated Mass Spectrometrically from Peptides. J. Mol. Struct. (Theochem.) 1999, 468, 135.CrossRefGoogle Scholar
  43. 43.
    Tang, T.-H.; Fang, D.-C.; Harrison, A. G.; Csizmadia, I. G. A Computational Study of the Fragmentation of b3 Ions Derived from Protonated Peptides. J. Mol. Struct. (Theochem.) 2004, 675, 79.CrossRefGoogle Scholar
  44. 44.
    Gassman, P. G.; Tidwell, T. T. Electron-Deficient Carbocations. Acc. Chem. Res. 1983, 16, 279.CrossRefGoogle Scholar
  45. 45.
    Grutzmacher, H.-F.; Dommröse, A.-M. Kinetic Energy Release During CO Loss by Rearrangement of α-Benzoylcarbenium Ions. Org. Mass Spectrom 1983, 18, 601.CrossRefGoogle Scholar
  46. 46.
    Dommröse, A.-M.; Grutzmacher, H.-F. Destabilized Carbenium Ions. Secondary and Tertiary α-Acetylbenzyl Cation and α-Benzoylbenzyl Cation. Org. Mass Spectrom 1987, 22, 437.CrossRefGoogle Scholar
  47. 47.
    Wolf, R.; Grutzmacher, H.-F. Destabilized Carbenium Ions. α-Carbomethoxy-α,α-Dimethylmethyl Cation. Org. Mass Spectrom. 1989, 24, 398.CrossRefGoogle Scholar
  48. 48.
    Tkaczyk, M.; Harrison, A. G. Formation of Destabilized Carbenium Ions by Charge Inversion of Negative Ions. Int. J. Mass Spectrom. Ion Processes 1991, 109, 295.CrossRefGoogle Scholar

Copyright information

© American Society for Mass Spectrometry 2004

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of TorontoTorontoCanada

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