[NMR paper] Solid-state NMR Shows that Dynamically Different Domains of Membrane Proteins Have Different Hydration Dependence.

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Solid-state NMR Shows that Dynamically Different Domains of Membrane Proteins Have Different Hydration Dependence.

Solid-state NMR Shows that Dynamically Different Domains of Membrane Proteins Have Different Hydration Dependence.

J Phys Chem B. 2014 Jul 15;

Authors: Zhang Z, Chen Y, Tang X, Li J, Wang L, Yang J

Abstract
Hydration has a profound influence on the structure, dynamics and functions of membrane and membrane-embedded proteins. So far hydration response of molecular dynamics of membrane proteins in lipid bilayers is poorly understood. Here, we reveal different hydration dependence of the dynamics in dynamically different domains of membrane proteins by multi-dimensional magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy using 121-residues integral diacylglycerol kinase (DAGK) in 1,2-dimyristoyl-sn-glycero-3- phosphocholine (DMPC)/1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DMPG) lipid bilayers as a model system. The highly mobile and immobile domains of DAGK and their water accessibility are identified site-specifically by scalar- and dipolar-coupling based MAS ssNMR experiments, respectively. Our experiments reveal different hydration dependence of the dynamics in highly mobile and immobile domains of membrane proteins. We demonstrate that the fast, large-amplitude motions in highly mobile domains are not triggered until 20% hydration, enhanced at 20-50% hydration and unchanged at above 50% hydration. In contrast, motions on sub-microsecond time scale of immobile residues are observed to be independent of the hydration levels in gel phase of lipids; and at the temperature near gel-liquid crystalline phase transition, amplitude of whole-molecule rotations around the bilayer normal is dominated by the fluidity of lipid bilayers, which is strongly hydration dependent. The hydration dependence of the dynamics of DAGK revealed by this study provides new insights into the correlations of hydration-dynamics-function of membrane proteins in lipid bilayers.


PMID: 25026099 [PubMed - as supplied by publisher]



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