Transcript of Modification of the Prolyl Ring of Val-Pro-Ala and the Impact of this Modification on b 2 Ion...
- Slide 1
- Modification of the Prolyl Ring of Val-Pro-Ala and the Impact
of this Modification on b 2 Ion Structure Matthew Bernier, Julia
Chamot-Rooke, Ashley Gucinski, & Vicki Wysocki International
Symposium on Molecular Spectroscopy 68th Meeting 6/19/13
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- Roepstorff P, Fohlman J. Biomed. Mass Spectrom. (1984) 11 (11):
601. b2b2 y2y2 b fragment ion formation Collision induced
dissociation (Ar/He)
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- oxazolone diketopiperazine cis trans b fragment ion
formation
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- VS Isomerization (trans-cis) Rel. Energy 20 kcal/mol 13
kcal/mol JACS, 1988. 110(13): p. 4212-4216. 2.5 kcal/mol 0.5
kcal/mol What makes proline so special?
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- Gucinski et al. Phys Chem A 2013. Just Accepted Only ONE of the
XxxPro peptides here show no evidence of diketopiperazine b 2
structure What makes proline so special?
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- Collagen Triple Helix: Substituent stability Biopolymers, Vol.
59, 2428 (2001) PNAS January 12, 2010 vol. 107, 559564 ProHypGly
ProProGly 30.5 C 36 C TmTm
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- Collagen Triple Helix: Substituent stability PNAS January 12,
2010 vol. 107, 559564 34 C 58 C TmTm
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- J. Org. Chem. 2004, 69, 8565-8573. J. Am. Chem. Soc., Vol. 123,
No. 4, 2001 Effects of prolyl ring substitution X = H, OH, or F Y =
H X = H Y = OH or F
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- J. Org. Chem. 2004, 69, 8565-8573. Can we influence
oxazolone/diketo prevalance with substituent influence on trans/cis
isomerization barrier? Effects of prolyl ring substitution
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- Does wavelength excite vibrational mode of molecule? Yes
Fragmentation Efficiency No + No fragments = no intensity @
wavenumber scanned + Molecule of interest ionized into the gas
phase + MS trapping and irradiation with tunable IR laser
Electrospray Ionization (ESI) Fragmentation Efficiency: I fragments
/ I precursor + + OR Fragment ions detected- measurable intensity
at vibrationally active energy CLIO Infrared Laser Tunable
1000-2000 cm -1 Action Infrared Multi-Photon Dissociation
Spectroscopy
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- K trans/cis = 4.6 ValXxx Vibrational Spectroscopy - ValPro
Gucinski, A. C.; Chamot-Rooke, J.; Steinmetz, V.; Somogyi, A.;
Wysocki, V. H. J Phys Chem A 2013, 117, 1291.
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- ValXxx Vibrational Spectroscopy Val(Y-Flp) K trans/cis = 6.7 J.
Org. Chem. 2004, 69, 8565-8573.
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- ValXxx Vibrational Spectroscopy Val(X-Flp) K trans/cis = 2.5 J.
Org. Chem. 2004, 69, 8565-8573.
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- ValXxx Vibrational Spectroscopy K trans/cis = 2.5 K trans/cis =
4.6 K trans/cis = 6.7 Gucinski, A. C.; Chamot-Rooke, J.; Steinmetz,
V.; Somogyi, A.; Wysocki, V. H. J Phys Chem A 2013, 117, 1291.
X-Flp Y-Flp Pro x10 x25 x50
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- Gas phase vs. solution phase structure
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- Y-FlpX-Flp Oxazolone Diketopiperazine
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- Tandem MS 3 comparison: V(Xflp) vs V(YFlp) Oxazolone
Diketopiperazine
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- Conclusions Holds true in gas phase
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- Acknowledgments NIH GMR01-51387