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Decay and cooling of biomolecules in an electrostatic storage ring

June 27 -July 2, 2003      4rth annual LEIF meeting - Belfast, N. Ireland. 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. Ubiquitin. 76 amino acid protein 8.6 k amu.

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Decay and cooling of biomolecules in an electrostatic storage ring

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  1. June 27 -July 2, 2003      4rth annual LEIF meeting - Belfast, N. Ireland 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

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

  3. Common amino acids

  4. Photo absorption Tryptophan Tyrosine Photo absorption in solution Phenylalanine

  5. Moleculesinvestigated Lys-Trp-Lys Trp

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

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

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

  9. h Heating by photo absorption Tr Photo absorption in solution

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

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

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

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

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

  16. Fluorescence

  17. Solvent Amino Acid Polypeptide Emission Quantum Emission Quantum Phenylalanine DMSO 282 0.02 284 0.006 Tyrosine DMSO 306 0.27 309 0.06 Tyrosine H20 303 0.21 -- -- Tryptophan DMSO 340 0.81 333 0.67 Tryptophan H20 340 0.19 333. 0.02 Quantum yield Quantum yield is very sensitive to the environment. (Amino Acid) > (Polypeptide) DMSO > H20

  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

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