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Your search keyword '"Hamm, Peter"' showing total 18 results
Start Over Author "Hamm, Peter" Publisher proceedings of the national academy of sciences
18 results on '"Hamm, Peter"'

2. Vibrational couplings between protein and cofactor in bacterial phytochrome Agp1 revealed by 2D-IR spectroscopy

Author

Buhrke, David, Michael, Norbert, Hamm, Peter, University of Zurich, and Buhrke, David

Subjects
10120 Department of Chemistry, 1000 Multidisciplinary, Multidisciplinary, Bacterial Proteins, Spectrum Analysis, 540 Chemistry, Phytochrome, Vibration
Abstract

Phytochromes are ubiquitous photoreceptor proteins that undergo a significant refolding of secondary structure in response to initial photoisomerization of the chromophoric group. This process is important for the signal transduction through the protein and thus its regulatory function in different organisms. Here, we employ two-dimensional infrared absorption (2D-IR) spectroscopy, an ultrafast spectroscopic technique that is sensitive to vibrational couplings, to study the photoreaction of bacterial phytochrome Agp1. By calculating difference spectra with respect to the photoactivation, we are able to isolate sharp difference cross-peaks that report on local changes in vibrational couplings between different sites of the chromophore and the protein. These results indicate inter alia that a dipole coupling between the chromophore and the so-called tongue region plays a role in stabilizing the protein in the light-activated state.

Published
2022

7. Kinetic response of a photoperturbed allosteric protein

Author

Buchli, Brigitte, primary, Waldauer, Steven A., additional, Walser, Reto, additional, Donten, Mateusz L., additional, Pfister, Rolf, additional, Blöchliger, Nicolas, additional, Steiner, Sandra, additional, Caflisch, Amedeo, additional, Zerbe, Oliver, additional, and Hamm, Peter, additional

Published
2013
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10. Energy transport in peptide helices

Author

Botan, Virgiliu, primary, Backus, Ellen H. G., additional, Pfister, Rolf, additional, Moretto, Alessandro, additional, Crisma, Marco, additional, Toniolo, Claudio, additional, Nguyen, Phuong H., additional, Stock, Gerhard, additional, and Hamm, Peter, additional

Published
2007
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17. Impact of nuclear quantum effects on the structural inhomogeneity of liquid water

Author

Andrey Shalit, David Sidler, Peter Hamm, Gustavo Ciardi, Arian Berger, University of Zurich, and Hamm, Peter

Subjects
10120 Department of Chemistry, 1000 Multidisciplinary, Multidisciplinary, Materials science, Isotope, Liquid water, Hydrogen bond, Intermolecular force, 02 engineering and technology, Effective temperature, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Freezing point, Quantum mechanics, Physical Sciences, 540 Chemistry, 0210 nano-technology, Thz spectroscopy
Abstract

Significance The degree to which water is structured is an extremely intriguing problem and a matter of ongoing debate. To that end, we studied the 2D Raman–terahertz response of liquid water in dependence of temperature and isotope substitution, considering H 2 O, D 2 O, and H 2 18 O. A very short-lived echo is observed, whose lifetime slows down with decreasing temperature. It differs for D 2 O versus H 2 O, whereas that of H 2 18 O versus H 2 O is the same. The comparison of the three isotopologues allows us to disentangle nuclear quantum effects from trivial dynamical mass effects. The former dominate the echo lifetime, hence, it is concluded that it is a measure of the heterogeneity of the hydrogen bond networks of water.

Published
2019

18. Kinetic response of a photoperturbed allosteric protein

Author

Reto Walser, Peter Hamm, Sandra Steiner, Rolf Pfister, Mateusz L. Donten, Steven A. Waldauer, Oliver Zerbe, Nicolas Blöchliger, Brigitte Buchli, Amedeo Caflisch, University of Zurich, and Hamm, Peter

Subjects
Models, Molecular, 10120 Department of Chemistry, Magnetic Resonance Spectroscopy, Time Factors, Spectrophotometry, Infrared, Photochemistry, Protein Conformation, Allosteric regulation, PDZ domain, Protein Tyrosine Phosphatase, Non-Receptor Type 13, Molecular Dynamics Simulation, 01 natural sciences, 03 medical and health sciences, Molecular dynamics, chemistry.chemical_compound, Protein structure, Allosteric Regulation, 540 Chemistry, 0103 physical sciences, 10019 Department of Biochemistry, Humans, 030304 developmental biology, 1000 Multidisciplinary, 0303 health sciences, Multidisciplinary, 010304 chemical physics, biology, Photoswitch, Lasers, Water, Nuclear magnetic resonance spectroscopy, Kinetics, Allosteric enzyme, Azobenzene, chemistry, Physical Sciences, biology.protein, Biophysics, 570 Life sciences, Azo Compounds
Abstract

By covalently linking an azobenzene photoswitch across the binding groove of a PDZ domain, a conformational transition, similar to the one occurring upon ligand binding to the unmodified domain, can be initiated on a picosecond timescale by a laser pulse. The protein structures have been characterized in the two photoswitch states through NMR spectroscopy and the transition between them through ultrafast IR spectroscopy and molecular dynamics simulations. The binding groove opens on a 100-ns timescale in a highly nonexponential manner, and the molecular dynamics simulations suggest that the process is governed by the rearrangement of the water network on the protein surface. We propose this rearrangement of the water network to be another possible mechanism of allostery.

Published
2013

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