Journal of magnetic resonance最新文献_第5页

Non-commutative perturbation theory for spin dynamics explains the factorization properties of RIDME background 自旋动力学的非交换性扰动理论解释了 RIDME 背景的因式分解特性

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-07-02 DOI: 10.1016/j.jmr.2024.107729

Sergei Kuzin, Maxim Yulikov, Gunnar Jeschke

{"title":"Non-commutative perturbation theory for spin dynamics explains the factorization properties of RIDME background","authors":"Sergei Kuzin, Maxim Yulikov, Gunnar Jeschke","doi":"10.1016/j.jmr.2024.107729","DOIUrl":"10.1016/j.jmr.2024.107729","url":null,"abstract":"<div><p>The intermolecular hyperfine relaxation-induced dipolar modulation enhancement (ih-RIDME) experiment has a promising potential to quantitatively characterize the nuclear environment in the 0.8-3 nm range around an electron spin. Such information about the spatial arrangement of nuclei is of great interest for structural biology as well as for dynamic nuclear polarization (DNP) methods. In order to develop a reliable and sensitive spectroscopic tool, a solid data model needs to be established. Here, we attempt to provide a theoretical explanation for the experimentally observed properties of the ih-RIDME signal. Our main approach uses a perturbation expansion of the Baker–Campbell–Hausdorff formula during the transverse evolution of the electron spin, treating the nuclear dipolar Hamiltonian as a perturbation. We show that a product structure of the ih-RIDME signal follows directly from the statistical independence of the perturbation terms and the multinuclear hyperfine coupling, and that this signal composition is expected when the mixing time exceeds the 95% decay of the Hahn echo.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"365 ","pages":"Article 107729"},"PeriodicalIF":2.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1090780724001137/pdfft?md5=69c31975fef8deaf55a79d77abbadb2f&pid=1-s2.0-S1090780724001137-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hyperpolarized nuclear Overhauser enhancement of alanine methyl groups by doubly relayed proton exchange 通过双中继质子交换增强丙氨酸甲基基团的超极化核奥弗豪斯效应。

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-07-01 DOI: 10.1016/j.jmr.2024.107727

Milan Zachrdla , Ertan Turhan , Christopher Pötzl , Aude Sadet , Paul R. Vasos , Dennis Kurzbach

{"title":"Hyperpolarized nuclear Overhauser enhancement of alanine methyl groups by doubly relayed proton exchange","authors":"Milan Zachrdla , Ertan Turhan , Christopher Pötzl , Aude Sadet , Paul R. Vasos , Dennis Kurzbach","doi":"10.1016/j.jmr.2024.107727","DOIUrl":"10.1016/j.jmr.2024.107727","url":null,"abstract":"<div><p>Hyperpolarized water in dissolution dynamic nuclear polarization (dDNP) experiments has emerged as a promising method for enhancing nuclear magnetic resonance (NMR) signals, particularly in studies of proteins and peptides. Herein, we focus on the application of “proton exchange-doubly relayed” nuclear Overhauser effects (NOE) from hyperpolarized water to achieve positive signal enhancement of methyl groups in the side chain of an alanine-glycine peptide. In particular, we show a cascade hyperpolarization transfer. Initial proton exchange between solvent and amide introduces hyperpolarization into the peptide. Subsequently, intermolecular NOE relays the hyperpolarization first to Ala-H<sup>α</sup> and then in a second step to the Ala-CH<sub>3</sub> moiety. Both NOEs have negative signs. Hence, the twice-relayed NOE pathway leads to a positive signal enhancement of the methyl group with respect to the thermal equilibrium magnetization. This effect might indicate a way towards hyperpolarized water-based signal enhancement for methyl groups, which are often used for NMR studies of large proteins in solution.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107727"},"PeriodicalIF":2.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1090780724001113/pdfft?md5=794ed5d93963c4dacc14fabd5dbbbcf8&pid=1-s2.0-S1090780724001113-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Bayesian analysis of 1D 1H-NMR spectra 对一维 1H-NMR 光谱进行贝叶斯分析

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-07-01 DOI: 10.1016/j.jmr.2024.107723

Flavio De Lorenzi , Tom Weinmann , Simon Bruderer , Björn Heitmann , Andreas Henrici , Simon Stingelin

{"title":"Bayesian analysis of 1D 1H-NMR spectra","authors":"Flavio De Lorenzi , Tom Weinmann , Simon Bruderer , Björn Heitmann , Andreas Henrici , Simon Stingelin","doi":"10.1016/j.jmr.2024.107723","DOIUrl":"10.1016/j.jmr.2024.107723","url":null,"abstract":"<div><p>Extracting spin system parameters from 1D high resolution <span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H-NMR spectra can be an intricate task requiring sophisticate methods. With a few exceptions methods to perform such a total line shape analysis commonly rely on local optimization techniques which for increasing complexity of the underlying spin system tend to reveal local solutions. In this work we propose a full Bayesian modeling approach based on a quantum mechanical model of the spin system. The Bayesian formalism provides a global optimization strategy which allows to efficiently include prior knowledge about the spin system or to incorporate additional constraints concerning the parameters of interest. The proposed algorithm has been tested on synthetic and real 1D <span><math><msup><mrow></mrow><mrow><mn>1</mn></mrow></msup></math></span>H-NMR data for various spin systems with increasing complexity. The results show that the Bayesian algorithm provides accurate estimates even for complex spectra with many overlapping regions, and that it can cope with symmetry induced local minima. By providing an unbiased estimate of the model evidence the proposed algorithm furthermore offers a way to discriminate between different spin system candidates.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107723"},"PeriodicalIF":2.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1090780724001071/pdfft?md5=4f020270c8b884b725a432b117255c09&pid=1-s2.0-S1090780724001071-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141414257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

AlphaFold2 as a replacement for solution NMR structure determination of small proteins: Not so fast! AlphaFold2 可替代小蛋白质的溶液 NMR 结构测定：没那么快

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-07-01 DOI: 10.1016/j.jmr.2024.107725

Jeffrey P. Bonin , James M. Aramini , Ying Dong , Hao Wu , Lewis E. Kay

{"title":"AlphaFold2 as a replacement for solution NMR structure determination of small proteins: Not so fast!","authors":"Jeffrey P. Bonin , James M. Aramini , Ying Dong , Hao Wu , Lewis E. Kay","doi":"10.1016/j.jmr.2024.107725","DOIUrl":"10.1016/j.jmr.2024.107725","url":null,"abstract":"<div><p>The determination of a protein’s structure is often a first step towards the development of a mechanistic understanding of its function. Considerable advances in computational protein structure prediction have been made in recent years, with AlphaFold2 (AF2) emerging as the primary tool used by researchers for this purpose. While AF2 generally predicts accurate structures of folded proteins, we present here a case where AF2 incorrectly predicts the structure of a small, folded and compact protein with high confidence. This protein, pro-interleukin-18 (pro-IL-18), is the precursor of the cytokine IL-18. Interestingly, the structure of pro-IL-18 predicted by AF2 matches that of the mature cytokine, and not the corresponding experimentally determined structure of the pro-form of the protein. Thus, while computational structure prediction holds immense promise for addressing problems in protein biophysics, there is still a need for experimental structure determination, even in the context of small well-folded, globular proteins.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107725"},"PeriodicalIF":2.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1090780724001095/pdfft?md5=1102169d5b575472beeb169492cb1f71&pid=1-s2.0-S1090780724001095-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and optimization of THz coupling in zirconia MAS rotors for dynamic nuclear polarization NMR 设计和优化氧化锆 MAS 转子中的太赫兹耦合，用于动态核偏振 NMR

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-07-01 DOI: 10.1016/j.jmr.2024.107722

Guangjiang Li , Blake Dastrup , Ravi Shankar Palani , Michael A. Shapiro , Sudheer K. Jawla , Robert G. Griffin , Keith A. Nelson , Richard J. Temkin

{"title":"Design and optimization of THz coupling in zirconia MAS rotors for dynamic nuclear polarization NMR","authors":"Guangjiang Li , Blake Dastrup , Ravi Shankar Palani , Michael A. Shapiro , Sudheer K. Jawla , Robert G. Griffin , Keith A. Nelson , Richard J. Temkin","doi":"10.1016/j.jmr.2024.107722","DOIUrl":"10.1016/j.jmr.2024.107722","url":null,"abstract":"<div><p>We present 3D electromagnetic simulations of the coupling of a 250 GHz beam to the sample in a 380 MHz DNP NMR spectrometer. To obtain accurate results for magic angle spinning (MAS) geometries, we first measured the complex dielectric constants of zirconia, sapphire, and the sample matrix material (DNP juice) from room temperature down to cryogenic temperatures and from 220 to 325 GHz with a VNA and up to 1 THz with a THz TDS system. Simulations of the coupling to the sample were carried out with the ANSYS HFSS code as a function of the rotor wall material (zirconia or sapphire), the rotor wall thickness, and the THz beam focusing (lens or no lens). For a zirconia rotor, the <em>B<sub>1</sub></em> field in the sample was found to be strongly dependent on the rotor wall thickness, which is attributed to the high refractive index of zirconia. The optimum thickness of the wall is likely due to a transmission maximum but is offset from the thickness predicted by a simple calculation for a flat slab of the wall material. The <em>B<sub>1</sub></em> value was found to be larger for a sapphire rotor than for a zirconia rotor for all cases studied. The results found in this work provide new insights into the coupling of THz radiation to the sample and should lead to improved designs of future DNP NMR instrumentation.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107722"},"PeriodicalIF":2.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S109078072400106X/pdfft?md5=db8b4347b8201c62a1b0d4f9ecebf092&pid=1-s2.0-S109078072400106X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141404789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cross polarization stability in multidimensional NMR spectroscopy of biological solids 生物固体多维核磁共振光谱中的交叉极化稳定性。

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-06-23 DOI: 10.1016/j.jmr.2024.107724

Benjamin D. Harding , Alexander M. Barclay , Dennis W. Piehl , Ashley Hiett , Owen A. Warmuth , Ruixian Han , Katherine Henzler-Wildman , Chad M. Rienstra

{"title":"Cross polarization stability in multidimensional NMR spectroscopy of biological solids","authors":"Benjamin D. Harding , Alexander M. Barclay , Dennis W. Piehl , Ashley Hiett , Owen A. Warmuth , Ruixian Han , Katherine Henzler-Wildman , Chad M. Rienstra","doi":"10.1016/j.jmr.2024.107724","DOIUrl":"10.1016/j.jmr.2024.107724","url":null,"abstract":"<div><p>Magic-angle spinning (MAS) solid-state nuclear magnetic resonance (SSNMR) spectroscopy is a powerful and versatile technique for probing structure and dynamics in large, insoluble biological systems at atomic resolution. With many recent advances in instrumentation and polarization methods, technology development in SSNMR remains an active area of research and presents opportunities to further improve data collection, processing, and analysis of samples with low sensitivity and complex tertiary and quaternary structures. SSNMR spectra are often collected as multidimensional data, requiring stable experimental conditions to minimize signal fluctuations (t<sub>1</sub> noise). In this work, we examine the factors adversely affecting signal stability as well as strategies used to mitigate them, considering laboratory environmental requirements, configuration of amplifiers, and pulse sequence parameter selection. We show that Thermopad® temperature variable attenuators (TVAs) can partially compensate for the changes in amplifier output power as a function of temperature and thereby ameliorate one significant source of instability for some spectrometers and pulse sequences. We also consider the selection of tangent ramped cross polarization (CP) waveform shapes, to balance the requirements of sensitivity and instrumental stability. These findings collectively enable improved stability and overall performance for CP-based multidimensional spectra of microcrystalline, membrane, and fibrous proteins performed at multiple magnetic field strengths.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"365 ","pages":"Article 107724"},"PeriodicalIF":2.0,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141592447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Solid-State NMR 13C sensitivity at high magnetic field 固态 NMR 13C 在高磁场下的灵敏度。

IF 2 3区化学

Journal of magnetic resonance Pub Date : 2024-06-18 DOI: 10.1016/j.jmr.2024.107709

Ruixian Han , Collin G. Borcik , Songlin Wang , Owen A. Warmuth , Kevin Geohring , Charles Mullen , Mario Incitti , John A. Stringer , Chad M. Rienstra

{"title":"Solid-State NMR 13C sensitivity at high magnetic field","authors":"Ruixian Han , Collin G. Borcik , Songlin Wang , Owen A. Warmuth , Kevin Geohring , Charles Mullen , Mario Incitti , John A. Stringer , Chad M. Rienstra","doi":"10.1016/j.jmr.2024.107709","DOIUrl":"10.1016/j.jmr.2024.107709","url":null,"abstract":"<div><p>Sensitivity is the foundation of every NMR experiment, and the signal-to-noise ratio (SNR) should increase with static (B<sub>0</sub>) magnetic field, by a proportionality that primarily depends on the design of the NMR probe and receiver. In the low B<sub>0</sub> field limit, where the coil geometry is much smaller than the wavelength of the NMR frequency, SNR can increase in proportion to B<sub>0</sub> to the power 7/4. For modern magic-angle spinning (MAS) probes, this approximation holds for rotor sizes up to 3.2 mm at 14.1 Tesla (T), corresponding to 600 MHz <sup>1</sup>H and 151 MHz <sup>13</sup>C Larmor frequencies. To obtain the anticipated benefit of larger coils and/or higher B<sub>0</sub> fields requires a quantitative understanding of the contributions to SNR, utilizing standard samples and protocols that reproduce SNR measurements with high accuracy and precision. Here, we present such a systematic and comprehensive study of <sup>13</sup>C SNR under MAS over the range of 14.1 to 21.1 T. We evaluate a range of probe designs utilizing 1.6, 2.5 and 3.2 mm rotors, including 24 different sets of measurements on 17 probe configurations using five spectrometers. We utilize N-acetyl valine as the primary standard and compare and contrast with other commonly used standard samples (adamantane, glycine, hexamethylbenzene, and 3-methylglutaric acid). These robust approaches and standard operating procedures provide an improved understanding of the contributions from probe efficiency, receiver noise figure, and B<sub>0</sub> dependence in a range of custom-designed and commercially available probes. We find that the optimal raw SNR is obtained with balanced 3.2 mm design at 17.6 T, that the best mass-limited SNR is achieved with a balanced 1.6 mm design at 21.1 T, and that the raw SNR at 21.1 T reaches diminishing returns with rotors larger than 2.5 mm.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"365 ","pages":"Article 107709"},"PeriodicalIF":2.0,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141592449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

MISSTEC-S: A fast 1H pulse calibration from spectra simultaneously produced by a spin echo and a stimulated echo MISSTEC-S：利用自旋回波和受激回波同时产生的光谱进行快速 1H 脉冲校准

IF 2.2 3区化学

Journal of magnetic resonance Pub Date : 2024-06-11 DOI: 10.1016/j.jmr.2024.107712

Margot Sanchez , Julien Pontabry , Gaëtan Assemat , Anthony Martinez , Serge Akoka

{"title":"MISSTEC-S: A fast 1H pulse calibration from spectra simultaneously produced by a spin echo and a stimulated echo","authors":"Margot Sanchez , Julien Pontabry , Gaëtan Assemat , Anthony Martinez , Serge Akoka","doi":"10.1016/j.jmr.2024.107712","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107712","url":null,"abstract":"<div><p>Radio-Frequency (RF) pulse calibration is an essential step in guaranteeing both optimum acquisition quality in multi-pulse NMR and accurate results in quantitative experiments. Most existing methods are based on a series of spectra for which the flip angle of one or more pulses is progressively incremented, implying a significant experiment time. In order to circumvent this drawback, we have previously proposed an approach based on the acquisition of a spin echo and a stimulated echo − the MISSTEC sequence − which requires only 8 s to determine the <span><math><mrow><msub><mrow><mi>PW</mi></mrow><mn>90</mn></msub></mrow></math></span>-<sup>1</sup>H, while it is several minutes in the case of the use of a nutation curve.</p><p>In this work, a new sequence for RF calibration is presented: MISSTEC-S. It is derived from the previously proposed MISSTEC sequence, but the observation of echoes in presence of magnetic field gradient is replaced by the observation of FIDs.</p><p>This modification allows both spectra to be phased, while imposing a strong constraint on the Mixing Time (TM). However, the relationship used to calculate the flip angle is only correct when TM is small enough to neglect longitudinal relaxation during this delay. In order to reduce TM, the first FID is truncated during acquisition and subsequently lengthened using points from the second FID. Results obtained with MISSTEC-S were compared to those obtained from a complete nutation curve and an excellent correlation was observed, although the experimental time to obtain the <span><math><mrow><msub><mrow><mi>PW</mi></mrow><mn>90</mn></msub></mrow></math></span> is dramatically reduced.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107712"},"PeriodicalIF":2.2,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141328503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Active shimming for a 25 T NMR superconducting magnet by spectrum convergence method 利用频谱收敛法为 25 T NMR 超导磁体主动垫片。

IF 2.2 3区化学

Journal of magnetic resonance Pub Date : 2024-06-10 DOI: 10.1016/j.jmr.2024.107711

Haoran Chen , Yaohui Wang , Wenchen Wang , Guyue Zhou , Pengfei Wu , Hongyi Qu , Jianhua Liu , Liang Li , Feng Liu

{"title":"Active shimming for a 25 T NMR superconducting magnet by spectrum convergence method","authors":"Haoran Chen , Yaohui Wang , Wenchen Wang , Guyue Zhou , Pengfei Wu , Hongyi Qu , Jianhua Liu , Liang Li , Feng Liu","doi":"10.1016/j.jmr.2024.107711","DOIUrl":"10.1016/j.jmr.2024.107711","url":null,"abstract":"<div><p>In the design of ultrahigh field nuclear magnetic resonance (NMR) superconducting magnets, it typically requires a high homogeneous magnetic field in the diameter of spherical volume (DSV) to obtain high spectrum resolution. However, shimming technique presents challenges due to the magnet bore space limitations, as accurate measurement of magnetic field distribution is very difficult, especially for customized micro-bore magnets. In this study, we introduced an active shimming method that utilized iterative adjustment of shim coil currents to improve the magnetic field homogeneity based on the full width at half maximum (FWHM) of the spectrum. The proposed method can determine the optimal set of currents for shim coils, effectively enhancing spatial field homogeneity by converging the FWHM. Experimental validation on a 25 T NMR superconducting magnet demonstrated the efficacy of the proposed method. Specifically, the active shimming method improved the field homogeneity of a 10 mm DSV from 7.09 ppm to 2.27 ppm with only four shim coils, providing a superior magnetic field environment for solid NMR and further magnetic resonance imaging (MRI) experiment. Furthermore, the proposed method can be promoted to more customized micro-bore magnets that require high magnetic field homogeneity.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107711"},"PeriodicalIF":2.2,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141332765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparison of methods for the NMR measurement of motionally averaged dipolar couplings 核磁共振测量运动平均偶极耦合的方法比较

IF 2.2 3区化学

Journal of magnetic resonance Pub Date : 2024-06-09 DOI: 10.1016/j.jmr.2024.107710

Scott A. Southern , Frédéric A. Perras

{"title":"Comparison of methods for the NMR measurement of motionally averaged dipolar couplings","authors":"Scott A. Southern , Frédéric A. Perras","doi":"10.1016/j.jmr.2024.107710","DOIUrl":"10.1016/j.jmr.2024.107710","url":null,"abstract":"<div><p>Motionally averaged dipolar couplings are an important tool for understanding the complex dynamics of catalysts, polymers, and biomolecules. While there is a plethora of solid-state NMR pulse sequences available for their measurement, in can be difficult to gauge the methods’ strengths and weaknesses. In particular, there has not been a comprehensive comparison of their performance in natural abundance samples, where <sup>1</sup>H homonuclear dipolar couplings are important and the use of large MAS rotors may be required for sensitivity reasons. In this work, we directly compared some of the more common methods for measuring C–H dipolar couplings in natural abundance samples using L-alanine (L-Ala) and the <em>N</em>-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLF) tripeptide as model systems. We evaluated their performance in terms of accuracy, resolution, sensitivity, and ease of implementation. We found that, despite the presence of <sup>1</sup>H homonuclear dipolar interactions, all methods, with the exception of REDOR, were able to yield the reasonable dipolar coupling strengths for both mobile and static moieties. Of these methods, PDLF provides the most convenient workflow and precision at the expense of low sensitivity. In low-sensitivity cases, MAS-PISEMA and DIPSHIFT appear to be the better options.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":"364 ","pages":"Article 107710"},"PeriodicalIF":2.2,"publicationDate":"2024-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141394083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0