6533b821fe1ef96bd127c4bf
RESEARCH PRODUCT
The protein dynamical transition does not require the protein polypeptide chain
Chiara CaronnaGiorgio SchiròAntonio CupaneMichael Marek KozaFrancesca Natalisubject
chemistry.chemical_classificationHydrogenProtein dynamicsProtein mean square displacementchemistry.chemical_elementNeutron scatteringHydrated powdersInelastic neutron scatteringAmino acidAmino acidCrystallographychemistry.chemical_compoundchemistryMyoglobinMolecular vibrationSide chainProtein dynamicGeneral Materials ScienceElastic neutron scatteringPhysical and Theoretical ChemistryChemical compositiondescription
We give experimental evidence that the main features of protein dynamics revealed by neutron scattering, i.e., the “protein dynamical transition” and the “boson peak”, do not need the protein polypeptide chain. We show that a rapid increase of hydrogen atoms fluctuations at about 220 K, analogous to the one observed in hydrated myoglobin powders, is also observed in a hydrated amino acids mixture with the chemical composition of myoglobin but lacking the polypeptide chain; in agreement with the protein behavior, the transition is abolished in the dry mixture. Further, an excess of low-frequency vibrational modes around 3 meV, typically observed in protein powders, is also observed in our mixture. Our results confirm that the dynamical transition is a water-driven onset and indicate that it mainly involves the amino acid side chains. Taking together the present data and recent results on the dynamics of a protein in denatured conformation and on the activity of dehydrated proteins, it can be concluded that the “protein dynamical transition” is neither a necessary nor a sufficient condition for active protein conformation and function.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-08-24 |