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.
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, T1, 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 0.5mol% of a copper-chelated lipid can significantly shorten T1 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.
Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, United States.
Kazutoshi
K
Yamamoto
Bruker BioSpin Corporation, 15 Fortune Drive, Billerica, MA 01821, United States.
Marc A
MA
Caporini
Department of Anesthesiology, University of Michigan, VA Medical Center, Ann Arbor, MI, United States.
Sangchoul
S
Im
Department of Anesthesiology, University of Michigan, VA Medical Center, Ann Arbor, MI, United States.
Lucy
L
Waskell
Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, United States. Electronic address: ramamoor@umich.edu.
Ayyalusamy
A
Ramamoorthy
D000818:Animals; D002247:Carbon Isotopes; D002614:Chelating Agents / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000737:chemistry*; D015786:Cytochromes b5 / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011817:Rabbits; D059629:Signal-To-Noise Ratio; D013696:Temperature
D002247:Carbon Isotopes; D002614:Chelating Agents; D008055:Lipids; D008565:Membrane Proteins; D009587:Nitrogen Isotopes; D003300:Copper; D015786:Cytochromes b5
Low-temperature; Membrane protein; Sensitivity