towards a molecular movie: transient 2d-ir spectroscopy peter hamm
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Towards a molecular movie: Transient 2D-IR spectroscopy
Peter Hamm
Physikalisch Chemisches Institut, Universität Zürich
B.L. de Groot and H. Grubmüller, Science 294, 2353-2357 (2001)http://www.mpibpc.gwdg.de/abteilungen/071/bgroot/gallery.html
Biosystems are Dynamical
Aquaporin-1
Structure Sensitive Methods
Scattering Methods(x-ray, electrons, neutrons) 2D-NMR
+ highest structure resolution power- works best in crystals
+ works best in solution+ high structure resolution power
+ intrinsic time resolution unlimited
- intrinsic time resolution very poor (1-100 ms)
Time Resolved Scattering Methods
2D-IR+ intrinsic time resolution fast (1 ps) - structure resolution power low but non-zero
Site Basis Exciton Basis
01
10
00
Coupled Vibrational States
O
O
NN
CC
2
1
H
Linear Coupling:
Frequency
CNH
C
O
CNH
C
O
CNH
C
OH
HH
CNH
C
OR1 C
NH
C
OR3
CNH
C
O R2
Frequency
Weak coupling,heterogeneous
Strong coupling,homogeneous
R2
R3R1
Linear Spectroscopy
tp=100 fs=200 cm-1
E=1 µJ Spectrometer +232 Element MCT
Detector ArrayFabry PerotFilter
Delay
Sample
2D-IR Spectroscopy: Setup
2D-IR Spectroscopy
O
O
NN
CC
|0
|1
|2
|0‘
|1‘
|2‘
2D-IR Spectroscopy
O
O
NN
CC
|10
|20 |11‘
|00‘
|01‘
|02‘
2D-IR Spectroscopy: Equilibrium
Woutersen et al. J. Phys. Chem. B, 104, 11316-11320 (2000)Woutersen et al., PNAS 98, 11254-11258 (2001)Woutersen et al. J. Chem. Phys. 117, 6833-6840 (2002)
1600
1620
1640
1660
1680
1700
Pum
p Fr
eque
ncy
[cm
-1]
1600 1620 1640 1660 1680 17001600 1620 1640 1660 1680 1700
Probe Frequency (cm-1)Probe Frequency [cm-1]
Conformation and distribution of conformations
Ultrafast equilibrium fluctuations
Our Dream: Molecular Movie
Photocleavable Peptide
C. Kolano, K. Gomann, W. Sander, Eur. J. Org. Chem. 2004, 20, 4167-4176.
h
?
1620 1640 1660 1680 1700 1720 1740 17600.0
0.1
0.2
Wavenumber [cm -1]
Abs
orba
nce
[mO
D]
Photocleavable Peptide: IR spectrum
Boc-Cys-Pro-Aib-Cys-OMe
1625 1650 1675 1700 1725
1625
1650
1675
1700
pu
[cm
-1]
pr
[cm -1]
Equilibrium 2D Spectrum
1 ps
t2D-IR
1625 1650 1675 1700 1725
1625
1650
1675
1700
pu
[cm
-1]
pr
[cm -1]
Equilibrium 2D Spectrum
1 ps
t2D-IR
1625 1650 1675 1700 1725
1625
1650
1675
1700
pu
[cm
-1]
pr
[cm -1]
Equilibrium 2D Spectrum
1 ps
t2D-IR
IR Probe
Spectrometer +232 Element MCT
Detector Array
Delay
SampleFlow-Cell
Transient 2D Spectroscopy: Setup
UV Switch
Delay
Fabry PerotFilterIR Pump
Transient 2D-IR Spectra 3-100 ps 1 ps
tIRpump IRprobe
UVpump
3 ps 25 ps 100 ps
• MD Package: Gromacs; Gromos Force Field 43a1 • Starting geometry: Based on low-resolution x-ray structure• Solvent box: Acetonitrile (1048 molecules)
Nonequilibrium MD Simulations
Equilibrium Simulation (NVT): 120 ns1 ns
Bondbreaking:Remove S-S Bond
Non
-Equ
ilibr
ium
Sim
ulat
ion
(N
VE
): 60
0 ps
0 100 200 300 400 500 600246
246
246
Time [ps]
OH
Dis
tanc
e [Å
]
MD Simulations: Example Trajectories
3.0 Å
0 100 200 300 400 500 600
2
3
4
5
6
OH
Dis
tanc
e [Å]
Time [ps]
MD Simulations: Average
3.0 Å
6.1 Å
+
-
1625 1650 1675 1700 1725
1625
1650
1675
1700
pu
[cm
-1]
pr
[cm -1]
Transient 2D-IR Spectra
Equilibrium 2D Transient 2D
100
ps
C. Kolano, Nature 2006 in press
1625 1650 1675 1700 1725
1625
1650
1675
1700
pu
[cm
-1]
pr
[cm -1]
Transient 2D-IR Spectra
Equilibrium 2D Transient 2D
100
ps
1625 1650 1675 1700 1725
1625
1650
1675
1700
pu
[cm
-1]
pr
[cm -1]
Transient 2D-IR Spectra
Equilibrium 2D Transient 2D
100
ps
And Finally: The Movie
Conclusion
Transient 2D-IR spectroscopy combines picosecond time resolution with microscopic structural information
Transient 2D-IR reveals new insight into fast structural dynamics of peptides, that
cannot be obtained otherwise.
An ultrafast molecular movie of the 3D-structure conceivable (in connection with isotope labeling)
Outlook: Isotope Labelling
h
13C=O13C=O
13C=18O13C=18O
-Helix Folding
University Zürich University Munich- Dr. Christoph Kolano - Prof. Wolfgang Zinth- Dr. Jens Bredenbeck - Dr. Jan Helbing University Bochum- Mariusz Kozinski - Dr. Christoph Kolano - Valentina Cervetto - Prof. Wolfram Sander- Harald Bregy- Ellen Backus Max Planck Institut, Martinsried - Virgiliu Botan - Dr. Christian Renner
- Prof. Luis MoroderMax Born Institut, Berlin- Dr. Sander Woutersen University of Toronto- Prof. Thomas Elsaesser - Prof. Andrew Woolley
University Frankfurt Financial Support- Prof. Josef Wachtveitl - Universität Zürich- Prof. Gerhards Stock - Swiss Science Foundation
- Deutsche Forschungsgemeinschaft
Acknowledgement
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