Dynamics of hydration water in deuterated purple membranes explored by neutron scattering
| العنوان: | Dynamics of hydration water in deuterated purple membranes explored by neutron scattering |
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| المؤلفون: | Brigitte Kessler, Giuseppe Zaccai, Martin Weik, Frank Gabel, Kathleen Wood, Dieter Oesterhelt, Marie Plazanet |
| المصدر: | European Biophysics Journal |
| بيانات النشر: | Springer Science and Business Media LLC, 2008. |
| سنة النشر: | 2008 |
| مصطلحات موضوعية: | Halobacterium salinarum, Dynamical transition, Time Factors, Movement, Neutron diffraction, Biophysics, Analytical chemistry, Neutron scattering, Hydration water dynamics, Neutron spectroscopy, Kinetic isotope effect, Lamellar structure, Original Paper, Chemistry, Dynamics (mechanics), Temperature, Membrane Proteins, Water, General Medicine, Deuterium, Purple membrane, Neutron Diffraction, Crystallography, Membrane |
| الوصف: | The function and dynamics of proteins depend on their direct environment, and much evidence has pointed to a strong coupling between water and protein motions. Recently however, neutron scattering measurements on deuterated and natural-abundance purple membrane (PM), hydrated in H2O and D2O, respectively, revealed that membrane and water motions on the ns–ps time scale are not directly coupled below 260 K (Wood et al. in Proc Natl Acad Sci USA 104:18049–18054, 2007). In the initial study, samples with a high level of hydration were measured. Here, we have measured the dynamics of PM and water separately, at a low-hydration level corresponding to the first layer of hydration water only. As in the case of the higher hydration samples previously studied, the dynamics of PM and water display different temperature dependencies, with a transition in the hydration water at 200 K not triggering a transition in the membrane at the same temperature. Furthermore, neutron diffraction experiments were carried out to monitor the lamellar spacing of a flash-cooled deuterated PM stack hydrated in H2O as a function of temperature. At 200 K, a sudden decrease in lamellar spacing indicated the onset of long-range translational water diffusion in the second hydration layer as has already been observed on flash-cooled natural-abundance PM stacks hydrated in D2O (Weik et al. in J Mol Biol 275:632–634, 2005), excluding thus a notable isotope effect. Our results reinforce the notion that membrane-protein dynamics may be less strongly coupled to hydration water motions than the dynamics of soluble proteins. |
| تدمد: | 1432-1017 0175-7571 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::190b082e764d6f5c06b5d05356bda852Test https://doi.org/10.1007/s00249-008-0285-0Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....190b082e764d6f5c06b5d05356bda852 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14321017 01757571 |
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