1. Shortening spin–lattice relaxation using a copper-chelated lipid at low-temperatures – A magic angle spinning solid-state NMR study on a membrane-bound protein
- Author
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Ayyalusamy Ramamoorthy, Lucy Waskell, Marc A. Caporini, Sang Choul Im, and Kazutoshi Yamamoto
- Subjects
Nuclear and High Energy Physics ,Resolution (mass spectrometry) ,Biophysics ,Analytical chemistry ,chemistry.chemical_element ,Signal-To-Noise Ratio ,Biochemistry ,Article ,Magic angle spinning ,Animals ,Chelation ,Nuclear Magnetic Resonance, Biomolecular ,Chromatography, High Pressure Liquid ,Chelating Agents ,chemistry.chemical_classification ,Carbon Isotopes ,Nitrogen Isotopes ,Biomolecule ,Temperature ,Spin–lattice relaxation ,Membrane Proteins ,Nuclear magnetic resonance spectroscopy ,Condensed Matter Physics ,Lipids ,Copper ,Cytochromes b5 ,Solid-state nuclear magnetic resonance ,chemistry ,lipids (amino acids, peptides, and proteins) ,Rabbits - Abstract
Inherent low sensitivity of NMR spectroscopy has been a major disadvantage, especially to study biomolecules like membrane proteins. Recent studies have successfully demonstrated the advantages of performing solid-state NMR experiments at very low and ultralow temperatures to enhance the sensitivity. However, the long spin–lattice relaxation time, T 1 , at very low temperatures is a major limitation. To overcome this difficulty, we demonstrate the use of a copper-chelated lipid for magic angle spinning solid-state NMR measurements on cytochrome-b5 reconstituted in multilamellar vesicles. Our results on multilamellar vesicles containing as small as 0.5 mol% of a copper-chelated lipid can significantly shorten T 1 of protons, which can be used to considerably reduce the data collection time or to enhance the signal-to-noise ratio. We also monitored the effect of slow cooling on the resolution and sensitivity of 13 C and 15 N signals from the protein and 13 C signals from lipids.
- Published
- 2013