Proton momentum distribution in a protein hydration shell

The momentum distribution of protons in the hydration shell of a globular protein has been measured through deep inelastic neutron scattering at 180 and 290 K, below and above the crossover temperature Tc=1.23Tg, where Tg=219 K is the glass transition temperature. It is found that the mean kinetic e...

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Bibliographic Details
Published in:Physical review letters 2007-03, Vol.98 (13), p.138102-138102, Article 138102
Main Authors: Senesi, R, Pietropaolo, A, Bocedi, A, Pagnotta, S E, Bruni, F
Format: Article
Language:English
Subjects:
Algorithms
DEEP INELASTIC SCATTERING
GLASS
HYDRATION
HYDROGEN
KINETIC ENERGY
MATERIALS SCIENCE
NEUTRON DIFFRACTION
Neutrons
POTENTIALS
PROTEINS
Proteins - chemistry
PROTONS
Scattering, Radiation
Temperature
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TRANSITION TEMPERATURE
TUNNEL EFFECT
WATER
Water - chemistry
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Summary:The momentum distribution of protons in the hydration shell of a globular protein has been measured through deep inelastic neutron scattering at 180 and 290 K, below and above the crossover temperature Tc=1.23Tg, where Tg=219 K is the glass transition temperature. It is found that the mean kinetic energy of the water hydrogens shows no temperature dependence, but the measurements are accurate enough to indicate a sensible change of momentum distribution and effective potential felt by protons, compatible with the transition from a single to a double potential well. This could support the presence of tunneling effects even at room temperature, playing an important role in biological function.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.98.138102