[NMR paper] Gd(3+)-chelated lipid accelerates solid-state NMR spectroscopy of seven-transmembrane proteins.

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Gd(3+)-chelated lipid accelerates solid-state NMR spectroscopy of seven-transmembrane proteins.

Related Articles Gd(3+)-chelated lipid accelerates solid-state NMR spectroscopy of seven-transmembrane proteins.

J Biomol NMR. 2017 May 30;:

Authors: Liu C, Liu J, Xu X, Xiang S, Wang S

Abstract
Solid-state NMR (SSNMR) is an attractive technique for studying large membrane proteins in membrane-mimetic environments. However, SSNMR experiments often suffer from low efficiency, due to the inherent low sensitivity and the long recycle delays needed to recover the magnetization. Here we demonstrate that the incorporation of a small amount of a Gd(3+)-chelated lipid, Gd(3+)-DMPE-DTPA, into proteoliposomes greatly shortens the spin-lattice relaxation time ((1)H-T 1) of lipid-reconstituted membrane proteins and accelerates the data collection. This effect has been evaluated on a 30*kDa, seven-transmembrane protein, Leptosphaeria rhodopsin. With the Gd(3+)-chelated lipid, we can perform 2D SSNMR experiments 3 times faster than by diamagnetic control. By combining this paramagnetic relaxation-assisted data collection with non-uniform sampling, the 3D experimental times are reduced eightfold with respect to traditional 3D experiments on diamagnetic samples. A comparison between the paramagnetic relaxation enhancement (PRE) effects of Cu(2+)- and Gd(3+)-chelated lipids indicates the much higher relaxivity of the latter. Hence, a tenfold lower concentration is needed for Gd(3+)-chelated lipids to achieve comparable PRE effects to Cu(2+)-chelated lipids. In addition, Gd(3+)-chelated lipids neither alter the protein structures nor induce significant line-width broadening of the protein signals. This work is expected to be beneficial for structural and dynamic studies of large membrane proteins by SSNMR.


PMID: 28560567 [PubMed - as supplied by publisher]



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