JCP Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

You Tube Flickr Twitter UniPHY Group iResearch App Facebook

Journal of Chemical Physics / Volume 135 / Issue 11 / ARTICLES / Gas Phase Dynamics and Structure: Spectroscopy, Molecular Interactions, Scattering, and Photochemistry
FREE

FULL-TEXT OPTIONS:

J. Chem. Phys. 135, 114301 (2011); http://dx.doi.org/10.1063/1.3625957 (7 pages)

Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies

Lidia Chomicz1, Janusz Rak1, Piotr Paneth2, Michael Sevilla3, Yeon Jae Ko4, Haopeng Wang4, and Kit H. Bowen4

1Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland
2Institute of Applied Radiation Chemistry, Technical University of Łódź, Żeromskiego 116, 90-924 Łódź, Poland
3Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA
4Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA

View MapView Map

(Received 8 June 2011; accepted 28 July 2011; published online 15 September 2011)

We report the photoelectron spectrum of anionic N-acetylproline, (N-AcPro)−, measured with 3.49 eV photons. This spectrum, which consists of a band centered at an electron binding energy of 1.4 eV and a higher energy spectral tail, confirms that N-acetylproline forms a valence anion in the gas phase. The neutrals and anions of N-AcPro were also studied computationally at the B3LYP/6-31++G(d,p) level. Based on the calculations, we conclude that the photoelectron spectrum is due to anions which originated from proton transfer induced by electron attachment to the π* orbital localized at the acetyl group of N-AcPro. We also characterized the energetics of reaction paths leading to pyrrolidine ring opening in the anionic N-AcPro. These data suggest that electron induced decomposition of peptides/proteins comprising proline strongly depends on the presence of proton donors in the close vicinity to the proline residue.

© 2011 American Institute of Physics

Article Outline

  1. INTRODUCTION
  2. EXPERIMENTAL METHODS
  3. COMPUTATIONS
  4. RESULTS AND DISCUSSION
    1. N -acetylproline photoelectron spectrum
    2. Neutral conformations
    3. Anion radicals
    4. Possible degradation pathways induced by an excess electron
  5. CONCLUSIONS

RELATED DATABASES

Web of Science

View this record in Web of Science

View Web of Science related articles

KEYWORDS and PACS

Keywords

binding energy, chemical exchanges, decomposition, density functional theory, electron attachment, negative ions, organic compounds, photoelectron spectra, proteins

PACS

  • 31.15.E-

    Density-functional theory

  • 33.60.+q

    Photoelectron spectra

  • 33.15.Ry

    Ionization potentials, electron affinities, molecular core binding energy

  • 34.80.Lx

    Recombination, attachment, and positronium formation

  • 82.30.Hk

    Chemical exchanges (substitution, atom transfer, abstraction, disproportionation, and group exchange)

ARTICLE DATA

Digital Object Identifier
http://dx.doi.org/10.1063/1.3625957

PUBLICATION DATA

ISSN

0021-9606 (print)  
1089-7690 (online)

Publisher

$abstract.society.value is a Member of CrossRef American Institute of Physics

  1. J. H. Miller, W. E. Wilson, and R. H. Ritchie, in Computational Approaches in Molecular Radiation Biology, edited by M. N. Varma and A. Chatterjee (Springer-Verlag, New York, 1994).
  2. B. R. Michael and P. ÒNeill, Science 287, 1603 (2000). [MEDLINE]
  3. M. Simic and E. J. Hayon, J. Phys. Chem. 77, 996 (1973). [CAS]
  4. D. Suryanarayana and M. D. Sevilla, J. Phys. Chem. 83, 1323 (1979). [CAS]
  5. M. D. Sevilla and V. L. Brooks, J. Phys. Chem. 77, 2954 (1973).
  6. R. A. Zubarev, D. M. Horn, E. K. Fridriksson, N. L. Kelleher, N. A. Kruger, M. A. Lewis, B. K. Carpenter, and F. W. McLafferty, Anal. Chem. 72, 563 (2000). [MEDLINE]
  7. E. A. Syrstad and F. Tureček, J. Am. Soc. Mass Spectrom. 16, 208 (2005). [MEDLINE]
  8. J. J. Coon, B. Ueberheide, J. E. P. Syka, D. D. Dryhurst, J. Ausio, J. Shabanowitz, and D. F. Hunt, Proc. Natl. Acad. Sci. U.S.A. 102, 9463 (2005).
  9. S. Hayakawa, M. Hashimoto, H. Matsubara, and F. Tureček, J. Am. Chem. Soc. 129, 7936 (2007). [MEDLINE]
  10. N. D. Udeshi, J. Shabanowitz, D. F. Hunt, and K. L. Rose, FEBS J. 274, 6269 (2007).
  11. F. Tureček, J. W. Jones, T. Towle, S. Panja, S. B. Nielsen, P. Hvelplund, and B. Paizs, J. Am. Chem. Soc. 130, 14584 (2008).
  12. F. Tureček, J. Am. Chem. Soc. 125, 5954 (2003). [MEDLINE]
  13. F. Tureček, X. Chen, and C. Hao, J. Am. Chem. Soc. 130, 8818 (2008).
  14. R. N. Grewal, H. E. Aribi, A. G. Harrison, K. W. M. Siu, and A. C. Hopkinson, J. Phys. Chem. B 108, 4899 (2004).
  15. J. Rak, K. Mazurkiewicz, M. Kobylecka, P. Storoniak, M. Harańczyk, I. Dąbkowska, R. A. Bachorz, M. Gutowski, D. Radisic, S. T. Stokes, S. N. Eustis, D. Wang, X. Li, Y. J. Ko, and K. H. Bowen, in Radiation Induced Molecular Phenomena in Nucleic Acids: A Comprehensive Theoretical and Experimental Analysis, edited by M. K. Shukla and J. Leszczyński (Springer-Verlag, Amsterdam, 2008).
  16. H. Abdoul-Carime and E. Illenberger, Chem. Phys. Lett. 397, 309 (2004). [Inspec] [CAS]
  17. P. Sulzer, E. Alizadeh, A. Mauracher, T. D. Märk, and P. Scheier, Int. J. Mass. Spectrom. 277, 274 (2008).
  18. M. Gerhards, O. C. Thomas, J. M. Nilles, W. J. Zheng, and K. H. Bowen, J. Chem. Phys. 116, 10247 (2002).
  19. S. T. Stokes, X. Li, A. Grubisic, Y. J. Ko, and K. H. Bowen, J. Chem. Phys. 127, 084321 (2007)JCPSA6000127000008084321000001. [MEDLINE]
  20. D. Svozil, P. Jungwith, and Z. Havlas, Collect. Czech. Chem. Commun. 69, 1395 (2004).
  21. A. E. Aliev and D. Courtier-Murias, J. Phys. Chem. B 111, 14034 (2007).
  22. A. E. Aliev, S. Bhandal, and D. Courtier-Murias, J. Phys. Chem. A 113, 10858 (2009).
  23. A. D. Becke, Phys. Rev. A 38, 3098 (1988).
  24. A. D. Becke, J. Chem. Phys. 98, 5648 (1993).
  25. C. Lee, W. Yang, and R. G. Parr, Phys. Rev. B 37, 785 (1988).
  26. R. Ditchfield, W. J. Hehre, and J. A. Pople, J. Chem. Phys. 54, 724 (1971)JCPSA6000054000002000724000001.
  27. W. J. Hehre, R. Ditchfield, and J. A. Pople, J. Chem. Phys. 56, 2257 (1972).
  28. J. C. Rienstra-Kiracofe, G. S. Tschumper, H. F. Schaefer, S. Nandi, and G. B. Ellison, Chem. Rev. 102, 231 (2002). [MEDLINE]
  29. J. Rak, P. Skurski, J. Simons, and M. Gutowski, J. Am. Chem. Soc. 123, 11695 (2001). [ISI] [MEDLINE] [CAS]
  30. M. J. Frisch, G. W. Trucks, H. B. Schlegel et al., GAUSSIAN 03, Gaussian, Inc., Wallingford, CT, 2004.
  31. GAUSSVIEW 5, Æ. Frisch, H. P. Hratchian, R. D. Dennington II, A. Todd, T. A. Keith, and J. Millam, Gaussian, Inc., Wallingford, CT, 2009.
  32. G. Schaftenaar and J. H. Noordik, J. Comput.-Aided Mol. Des. 14, 123 (2000). [MEDLINE]
  33. A. Szyperska, J. Rak, J. Leszczyński, X. Li, Y. J. Ko, H. Wang, and K. H. Bowen, J. Am. Chem. Soc. 131, 2663 (2009). [MEDLINE] [CAS]
  34. D. Schröder, C. A. Schalley, J. N. Harvey, and H. Schwarz, Int. J. Mass Spectrom. 185/186/187, 25 (1999).

Figures (5) Tables (3)

Figures (click on thumbnails to view enlargements)

FIG.1
Numbering of pyrrolidine's ring in N-acetylproline. The bond-cutting bars symbolize the considered breakages of the pyrrolidine ring in the N-AcPro anion: Path A – splitting of the N1-C2 bond, Path B – splitting of the N1-C5 bond.

FIG.1 Download High Resolution Image (.zip file) | Export Figure to PowerPoint

FIG.2
Conformers of the neutral and anionic N-AcPro – from the most stable one on the left to the least stable one on the right.

FIG.2 Download High Resolution Image (.zip file) | Export Figure to PowerPoint

FIG.3
Photoelectron spectrum of the (N-AcPro)− anion recorded with 3.49 eV photons (EBE = electron binding energy).

FIG.3 Download High Resolution Image (.zip file) | Export Figure to PowerPoint

FIG.4
Singly occupied molecular orbitals of N-AcPro anions plotted with a contour value of 0.03 bohr−3/2.

FIG.4 Download High Resolution Image (.zip file) | Export Figure to PowerPoint

FIG.5
Geometries and singly occupied molecular orbital (SOMO) distribution in stationary points (substrate, transition state, and product) on the reaction paths concerning the N-C bonds splitting (A – cleavage of the N1-C2 bond; B – cleavage of the N1-C5 bond) in the N-AcPro anions. Parts I and II refer to the cleavage of the pyrrolidine ring in an-exo-c and an-endo-t, respectively. ΔG and ΔG* denote the free energy of reaction and the activation free energy, respectively.

FIG.5 Download High Resolution Image (.zip file) | Export Figure to PowerPoint

Tables

Table I. Energetic characteristics of the neutral conformers of N-AcPro calculated at the B3LYP/6-31++G** level. ΔE, ΔH, and ΔG stand for the relative electronic energy, enthalpy, and free energy, respectively, calculated with respect to the neu-endo-t structure (the lowest energy conformer); all values given in kcal/mol.

View Table
Table II. Energetic characteristics of N-AcPro anion radical conformers along with their VDE and AEA values calculated at the B3LYP/6-31++G** level. ΔE, ΔH, and ΔG stand for the relative electronic energy, enthalpy, and free energy, respectively. The relative values are calculated with respect to the an-endo-t structure (the lowest energy conformer). ΔE, ΔH, ΔG, and AEAs in kcal/mol, VDE in eV.

View Table
Table III. Thermodynamic (ΔE, ΔG) and kinetic (ΔE*, ΔG*) barriers for breaking pyrrolidine's ring in two chosen anionic conformers along with VDE of broken-ring products. Paths A and B indicate the cleavage of the N1-C2 and N1-C5 bond, respectively; VDE in eV, all other values in kcal/mol.

View Table

Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Valence anions of N-acetylproline in the gas phase: Computational and anion photoelectron spectroscopic studies
  2. Aggregation of amphiphilic polymers in the presence of adhesive small colloidal particles
  3. Novel pentagonal silicon rings and nanowheels stabilized by flat pentacoordinate carbon(s)
  4. A water-swap reaction coordinate for the calculation of absolute protein–ligand binding free energies
  5. Multiple state transition interface sampling of alanine dipeptide in explicit solvent
Go to AIP Home
Copyright © American Institute of Physics
close