Decay and cooling of biomolecules in an electrostatic storage ring S. Tomita Department of Physics...
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Transcript of Decay and cooling of biomolecules in an electrostatic storage ring S. Tomita Department of Physics...
Decay and cooling of biomolecules in an electrostatic storage ring
S. Tomita
Department of Physics and AstronomyUniversity of Aarhus
DK-8000 Aarhus C, Denmark
June 27 -July 2, 2003 4rth annual LEIF meeting - Belfast, N. Ireland
Ubiquitin
76 amino acid protein8.6 k amu
40 Å
Helical structure: helixSheet structure: sheets
Common amino acids
Photo absorption in solution
Photo absorption
Tryptophan
Tyrosine
Phenylalanine
Absorption
Wavelength
Tryptophan 280 nm
Tyrosine 274 nm
Phenylalanine 257 nm
Molecules investigated
NH
CH
O
C
CH2
CH2
CH2
CH2
NH2
H NH
CH
O
C
CH2 CH
CNH
CC
CHCH
CH
CH
NH
CH
O
C
CH2
CH2
CH2
CH2
NH2
OH
CH
C
NH
CH2
CH
NH2 COOH
C
CH
CH
CHCH
Lys-Trp-Lys Trp
Electrospray
J.B. Fenn (1988)
Nobel Prize in Chemistry (2002)
~3kV
~1cm
~10 M/L~1 L/min
Electrospray Source
1 mbar 10-3 mbar 10-5 mbar 10-6 mbar
Rotarypump
Turbopump
Turbopump
Heatedcapillary
ESI needle4kV
Fused silicacapillary
22 pole Ion trap
Tube lensSkimmer
OctapoleLenses
Acceleration tube
ELISA
1 mDetector for neutrals
Laser
Accelerator with electrospray ion source
Magnet
Laser power meter
Injection
Channeltron
t
Cou
nt
s
Pulsed Alexandrite Laser240-270nm (3rd harmonic)Pulsed NdYAG Laser266nm (4th harmonic)
Photo absorption in solution
Heating by photo absorption
h
Tr
1/t decay law
))(exp( tEkg
dEtEkEkgtI ))(exp()()(
0))(exp()()(')(/)(' tEkEkEtkEkEk10 12 14 16 18 20
0.0
0.2
0.4
0.6
0.8
1.0
t=100 st = 1 ms t=10 s
t=0
g(E
)
Internal energy (eV)
Distribution at time t
Yield of decay
Maximum at Em(t)1/k = t at Em(t)
ttI /1)(
-15 -10 -5 0 5 10 15 20101
102
103
104
105
106
Co
un
ts
Time (ms)
[Lys-Trp-Lys+H]+ 266nm
NH
CH
O
C
CH2
CH2
CH2
CH2
NH2
H NH
CH
O
C
CH2 CH
CNH
CC
CHCH
CH
CH
NH
CH
O
C
CH2
CH2
CH2
CH2
NH2
OH
Injection
Laser
20 21 22 23 24 25100
101
102
103
Co
un
ts
Time (ms)
[Lys-Trp-Lys+H]+
20 21 22 23 24 25101
102
103
104
Co
un
ts
Time (ms)
243nm E = 5.10 eV = 0.48ms
260nm E = 4.77 eV = 0.86ms
Lower photon energyLonger life time
Higher photon energyShorter life time
1.10 1.15 1.20 1.25 1.30102
103
104
266nm260nm
De
cay
rate
(s-1
)
1/T (10-3K-1)
A=1.51010 s-1
Eb=1.10 eV
243nm
Arrhenius plot
We can determine pre-exponential factor and dissociation energy.
Tk
ETk
B
dexp)(
0 100 200 300 400 500 600 700 800 900 10000
1
2
3
4
5
6
7
8
9
10
Inte
rna
l en
erg
y (e
V)
Temperature (K)
243nm260nm
Dependence on temperature of ion trap
0 5 10 15 20101
102
103
104
105
106
Counts
Time (ms)
HOTCOLD
Temperature of ion trap
0 5 10 15 20101
102
103
104
105
106
Coutn
s
Time (ms)
[Trp+H]+ + 250nm
0 20 40 60 80101
102
103
104
105
Co
un
ts
Time (ms)
Injection Laser
CH
C
NH
CH2
CH
NH2 COOH
C
CH
CH
CHCH
10-1 100 101101
102
103
104
Counts
Time (ms)
1/t
Fluorescence
Quantum yield
SolventAmino 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 is very sensitive to the environment.
(Amino Acid) > (Polypeptide)DMSO > H20
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?
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