High-resolution 1H MAS RFDR NMR of biological membranes

Aucoin, Darryl; Camenares, Devin; Zhao, Xin; Jung, Jay Hoon; Sato, Takeshi; Smith, Steven O.

doi:10.1016/j.jmr.2008.12.009

Cited by 26 publications

(19 citation statements)

References 31 publications

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“…This approach has been previously applied to investigate the motional characteristics of resin and membrane-bound peptides. 27,28 A recent study on a membrane-bound antimicrobial peptide (MSI-78, also commercially known as pexiganan) also highlights the importance of this approach for the measurement of 1 H- 1 H residual dipolar couplings. 29 In this study, we extend this objective on a relatively large micelle-associated unlabeled cytochrome-b 5 (cytb 5 ) to gain better insights into its structure and dynamics.…”

Section: Introductionmentioning

confidence: 99%

Proton-detected 2D radio frequency driven recoupling solid-state NMR studies on micelle-associated cytochrome-b5

Pandey¹,

Vivekanandan²,

Yamamoto³

et al. 2014

Journal of Magnetic Resonance

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Solid-state NMR spectroscopy is increasingly used in the high-resolution structural studies of membrane-associated proteins and peptides. Most such studies necessitate isotopically labeled (13C, 15N and 2H) proteins/peptides, which is a limiting factor for some of the exciting membrane-bound proteins and aggregating peptides. In this study, we report the use of a proton-based slow magic angle spinning (MAS) solid-state NMR experiment that exploits the unaveraged 1H-1H dipolar couplings from a membrane-bound protein. We have shown that the difference in the buildup rates of cross peak intensities against the mixing time - obtained from 2D 1H-1H radio frequency-driven recoupling (RFDR) and nuclear Overhauser effect spectroscopy (NOESY) experiments on a 16.7-kDa micelle-associated full-length rabbit cytochrome-b5 (cytb5) - can provide insights into protein dynamics and could be useful to measure 1H-1H dipolar couplings. The experimental buildup curves compare well with theoretical simulations and are used to extract relaxation parameters. Our results show that due to fast exchange of amide protons with water in the soluble heme-containing domain of cyb5, coherent 1H-1H dipolar interactions are averaged out for these protons while alpha and side chain protons show residual dipolar couplings that can be obtained from 1H-1H RFDR experiments. The appearance of resonances with distinct chemical shift values in 1H-1H RFDR spectra enabled the identification of residues (mostly from the transmembrane region) of cytb5 that interact with micelles.

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Section: Introductionmentioning

confidence: 99%

Proton-detected 2D radio frequency driven recoupling solid-state NMR studies on micelle-associated cytochrome-b5

Pandey¹,

Vivekanandan²,

Yamamoto³

et al. 2014

Journal of Magnetic Resonance

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“…However, recent studies have shown the benefits of using 2D 1 H/ 1 H fp-RFDR experiments on mobile solids, such as model membranes, to recover motionally averaged dipolar couplings among protons[14, 15]. In addition, the ability of fast MAS enabled the use of fp-RFDR sequence with high 1 H spectral resolution [1, 3].…”

Section: Introductionmentioning

confidence: 99%

Finite-pulse radio frequency driven recoupling with phase cycling for 2D 1H/1H correlation at ultrafast MAS frequencies

Nishiyama¹,

Zhang²,

Ramamoorthy³

2014

Journal of Magnetic Resonance

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The first-order recoupling sequence radio frequency driven dipolar recoupling (RFDR) is commonly used in single-quantum/single-quantum homonuclear correlation 2D experiments under magic angle spinning (MAS) to determine homonuclear proximities. From previously reported analysis of the use of XY-based super-cycling schemes to enhance the efficiency of the finite-pulse-RFDR (fp-RFDR) pulse sequence, XY814 phase cycling was found to provide the optimum performance for 2D correlation experiments on low-γ nuclei. In this study, we analyze the efficiency of different phase cycling schemes for proton-based fp-RFDR experiments. We demonstrate the advantages of using a short phase cycle, XY4, and its super-cycle XY414 that only recouples the zero-quantum homonuclear dipolar coupling, for the fp-RFDR sequence in 2D 1H/1H correlation experiments at ultrafast MAS frequencies. The dipolar recoupling efficiencies of XY4, XY414 and XY814 phase cycling schemes are compared based on results obtained from 2D 1H/1H correlation experiments, utilizing the fp-RFDR pulse sequence, on powder samples of U-13C,15N-L-alanine, N-acetyl-15N-L-valyl-15N-L-leucine, and glycine. Experimental results and spin dynamics simulations show that XY414 performs the best when a high RF power is used for the 180° pulse, whereas XY4 renders the best performance when a low RF power is used. The effects of RF field inhomogeneity and chemical shift offsets are also examined. Overall, our results suggest that a combination of fp-RFDR-XY414 employed in the recycle delay with a large RF-field to decrease the recycle delay, and fp-RFDR-XY4 in the mixing period with a moderate RF-field, is a robust and efficient method for 2D single-quantum/single-quantum 1H/1H correlation experiments at ultrafast MAS frequencies.

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“…Eq. (34) indicates that B 0,app (r) can be controlled by time modulation of the RF field and auxiliary coil currents.…”

Section: Improved Methodsmentioning

confidence: 99%

“…On the other hand, techniques based on hardware system designs have been proposed for special applications in inhomogeneous fields. For example, magic-angle spinning (MAS) is as an effective tool for removing line broadening caused by chemical shift anisotropy and magnetic susceptibility discontinuities [33,34]. For example the Varian Nano-NMR probe is specifically designed for performing MAS on very small (≤ 40 μ L) samples, and can dramatically improve the resolution and sensitivity of proton signals of polymer support-bound compounds [35].…”

Section: Introductionmentioning

confidence: 99%