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Evidence of Surface Diffusion of Water Molecules on Proteins of Rabbit Lens by ¹H NMR Relaxation Measurements

Bodurka, Jerzy ; Buntkowsky, Gerd ; Gutsze, Aleksander (2022):
Evidence of Surface Diffusion of Water Molecules on Proteins of Rabbit Lens by ¹H NMR Relaxation Measurements. (Publisher's Version)
In: Zeitschrift für Naturforschung C, 51 (1-2), pp. 81-90. De Gruyter, ISSN 0939-5075, e-ISSN 1865-7125,
DOI: 10.26083/tuprints-00018892,
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Item Type: Article
Origin: Secondary publication service
Status: Publisher's Version
Title: Evidence of Surface Diffusion of Water Molecules on Proteins of Rabbit Lens by ¹H NMR Relaxation Measurements
Language: English
Abstract:

In this work, we propose a relaxation model for the interpretation of NMR proton spinlattice and spin-spin relaxation times of mammalian lenses. The framework for this model is based on nuclear magnetic spin-lattice relaxation measurements as a function of temperature at different Larmor frequencies for whole rabbit lenses and fragments of the lens. According to this model, two different dynamic processes of the water molecules determine the relaxation behaviour, namely rotational diffusion and translational surface diffusion. These dynamic processes in conjuction with a two site exchange model give a good explanation of all the measured relaxation data. From the experimental data, we were able to obtain the activation parameters for rotational and translational diffusion of bound lens water. Correlation times of 2.1x10⁻¹¹ sec and 2.5x10⁻⁹ sec and activation energies of 20.5 kJ/mol and 22.5 kJ/mol respectively were found at 308K. At low Larmor frequencies (≤100 MHz) the longitudinal relaxation is mainly determined by translational surface diffusion of bound water with a mean square displacement of 1.5 nm, whereas at higher frequencies (≥300 MHz), rotational diffusion is the main relaxation mechanism. The spin-spin relaxation is determined by translational diffusion over the whole frequency range and therefore shows only a very small dispersion. By our model it is possible to explain: 1) the strikingly large difference between the T₁ value and the T₂A and T₂B values observed in the lens and 2) the different values of the activation energies measured at different fields for the lens.

Journal or Publication Title: Zeitschrift für Naturforschung C
Journal volume: 51
Number: 1-2
Publisher: De Gruyter
Classification DDC: 500 Naturwissenschaften und Mathematik > 540 Chemie
Divisions: 07 Department of Chemistry > Physical Chemistry
Date Deposited: 10 Jan 2022 13:24
Last Modified: 10 Jan 2022 13:24
DOI: 10.26083/tuprints-00018892
Corresponding Links:
URN: urn:nbn:de:tuda-tuprints-188928
URI: https://tuprints.ulb.tu-darmstadt.de/id/eprint/18892
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