1. Decay and cooling of biomolecules in an electrostatic storage ring S. Tomita Department of Physics and Astronomy University of Aarhus DK-8000 Aarhus C, Denmark June 27 -July 2, 2003 4rth annual LEIF meeting - Belfast, N. Ireland4rth annual LEIF meeting

2. Ubiquitin 76 amino acid protein 8.6 k amu 40 Å Helical structure:  helix Sheet structure:  sheets

3. Common amino acids

4. Photo absorption in solution Photo absorption Tryptophan Tyrosine Phenylalanine Absorption Wavelength Tryptophan280 nm Tyrosine274 nm Phenylalanine257 nm

5. Molecules investigated Lys-Trp-LysTrp

6. Electrospray J.B. Fenn (1988) Nobel Prize in Chemistry (2002) ~3kV ~1cm ~10  M/L ~1  L/min

7. Electrospray Source 1 mbar 10 -3 mbar10 -5 mbar10 -6 mbar Rotary pump Turbo pump Turbo pump Heated capillary ESI needle 4kV Fused silica capillary 22 pole Ion trap Tube lens Skimmer Octapole Lenses Acceleration tube

8. ELISA 1 m Detector for neutrals Laser Accelerator with electrospray ion source Magnet Laser power meter Injection Channeltron t Counts Pulsed Alexandrite Laser 240-270nm (3 rd harmonic) Pulsed NdYAG Laser 266nm (4 th harmonic)

9. Photo absorption in solution Heating by photo absorption h TrTr

10. 1/t decay law Distribution at time t Yield of decay Maximum at E m (t) 1/k = t at E m (t)

11. [Lys-Trp-Lys+H] + 266nm Injection Laser

12. [Lys-Trp-Lys+H] + 243nm  E = 5.10 eV  = 0.48ms 260nm  E = 4.77 eV  = 0.86ms Lower photon energy Longer life time Higher photon energy Shorter life time

13. Arrhenius plot We can determine pre-exponential factor and dissociation energy. 243nm 260nm

14. Dependence on temperature of ion trap HOT COLD Temperature of ion trap

15. [Trp+H] + + 250nm InjectionLaser 1/t

16. Fluorescence

17. Quantum yield Solvent Amino AcidPolypeptide EmissionQuantumEmissionQuantum PhenylalanineDMSO2820.022840.006 TyrosineDMSO3060.273090.06 TyrosineH20H203030.21-- TryptophanDMSO3400.813330.67 TryptophanH20H203400.19333.0.02 Quantum yield is very sensitive to the environment. (Amino Acid) > (Polypeptide) DMSO > H 2 0

18. Summary Lys-Trp-Lys Narrow internal energy distribution Exponential decay after photo absorption Statistical decay through ergonic process Determination of dissociation energy Trp 1/t Decay Due to high fluorescence quantum yield?

19. Collaborators Stockholm H. Cederquist H.T. Schmidt J. Jensen H. Zettergren CAEN B.A. Huber B. Manil L. Maunoury Canada J.S. Forstar Group at Univ. of Aarhus P. Hvelplund J.U. Andersen S.B. Nielsen J. Rangama B. Liu