Journal of magnetic resonance最新文献

{"title":"Validating the 15N-1H HSQC-ROESY experiment for detecting 1HN exchange broadening in proteated proteins","authors":"Erik R.P. Zuiderweg","doi":"10.1016/j.jmr.2024.107676","DOIUrl":"10.1016/j.jmr.2024.107676","url":null,"abstract":"<div><p>It is advantageous to investigate milli-to-micro-second conformational exchange data contained in the solution NMR protein relaxation data other than ¹⁵N nuclei. Not only does one search under another lamp post, one also looks at dynamics at other time scales. The HSQC-ROESY ¹HN relaxation dispersion experiment for amide protons as introduced by <em>Ishima, et al (1998). J. Am. Soc. 120, 10534</em>–<em>10542,</em> is such an experiment, but has by the authors been advised to only be used for perdeuterated proteins to avoid complication with the ¹H–¹H multiple-spin effects. This is regretful, since not all proteins can be perdeuterated.</p><p>Here we analyze in detail the ¹HN relaxation terms for this experiment for a fully proteated protein. Indeed, the ¹HN relaxation theory is in this case complex and includes dipolar-dipolar relaxation interference and TOCSY transfers. With simulate both of these effects and show that the interference can be exploited for detecting exchange broadening. The TOCSY effect is shown to minor, and when it is not, a solution is provided. We apply the HSQC-ROESY experiment, with a small modification to suppress ROESY crosspeaks, to a 7 kDa GB1 protein that is just ¹⁵N and ¹³C labeled. At 10 °C we cannot detect any conformational exchange broadening: the ¹HN R₂ relaxation rates with 1.357 kHz spinlock field not larger than those recorded with a 12.136 kHz spinlock field. This means that there is no exchange broadening that can be differentially suppressed with the applied fields. Either there is no broadening, or the broadening is effectively suppressed by all fields, or the broadening cannot be suppressed by either of the fields. While initially this seems to be a disappointing result, we feel that this work establishes that the HSQC-ROESY experiment is very robust. It can indeed be utilized for proteated proteins upto about 30 kDa. This could be opening the study the milli-microsecond conformational dynamics as reported by ¹HN exchange broadening for many more proteins.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141132533","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}

{"title":"Magnetic Susceptibility Modeling of Magic-Angle Spinning Modules for Part Per Billion Scale Field Homogeneity","authors":"Jasmin Schönzart ,&nbsp;Ruixian Han ,&nbsp;Thomas Gennett ,&nbsp;Chad M. Rienstra ,&nbsp;John A. Stringer","doi":"10.1016/j.jmr.2024.107704","DOIUrl":"10.1016/j.jmr.2024.107704","url":null,"abstract":"<div><p>Magic-angle spinning (MAS) solid-state NMR methods are crucial in many areas of biology and materials science. Conventional probe designs have often been specified with 0.1 part per million (ppm) or 100 part per billion (ppb) magnetic field resolution, which is a limitation for many modern scientific applications. Here we describe a novel 5-mm MAS module design that significantly improves the linewidth and line shape for solid samples by an improved understanding of the magnetic susceptibility of probe materials and geometrical symmetry considerations, optimized to minimize the overall perturbation to the applied magnetic field (<em>B₀</em>). The improved spinning module requires only first and second order shimming adjustments to achieve a sub-Hz resolution of ¹³C resonances of adamantane at 150 MHz Larmor frequency (14.1<!--> <!-->Tesla magnetic field). Minimal use of third and higher order shims improves experimental reproducibility upon sample changes and the exact placement within the magnet. Furthermore, the shimming procedure is faster, and the required gradients smaller, thus minimizing thermal drift of the room temperature (RT) shims. We demonstrate these results with direct polarization (Bloch decay) and cross polarization experiments on adamantane over a range of sample geometries and with multiple superconducting magnet systems. For a direct polarization experiment utilizing the entire active sample volume of a 5-mm rotor (90 µl), we achieved full width at half maximum (FWHM) of 0.76 Hz (5 ppb) and baseline resolved the ¹³C satellite peaks for adamantane as a consequent of the 7.31 Hz (59 ppb) width at 2% intensity. We expect these approaches to be increasingly pivotal for high-resolution solid-state NMR spectroscopy at and above 1 GHz ¹H frequencies.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141140781","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}

{"title":"3D printing of ferromagnetic passive shims for field shaping in magnetic resonance imaging","authors":"Hanne Vanduffel ,&nbsp;Quentin Goudard ,&nbsp;An Vanduffel ,&nbsp;Sergey Basov ,&nbsp;Margriet J. Van Bael ,&nbsp;Cesar Parra-Cabrera ,&nbsp;Willy Gsell ,&nbsp;Rodrigo Oliveira-Silva ,&nbsp;Aleksander Matavz ,&nbsp;Wim Vanduffel ,&nbsp;Uwe Himmelreich ,&nbsp;Dimitrios Sakellariou ,&nbsp;Rob Ameloot","doi":"10.1016/j.jmr.2024.107702","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107702","url":null,"abstract":"<div><p>Magnetic Resonance Imaging (MRI) often encounters image quality degradation due to magnetic field inhomogeneities. Conventional passive shimming techniques involve the manual placement of discrete magnetic materials, imposing limitations on correcting complex inhomogeneities. To overcome this, we propose a novel 3D printing method utilizing binder jetting technology to enable precise deposition of a continuous range of concentrations of ferromagnetic ink. This approach grants complete control of the magnitude of the magnetic moment within the passive shim enabling tailored corrections of B₀ field inhomogeneities. By optimizing the magnetic field distribution using linear programming and an in-house written Computer-Aided Design (CAD) generation software, we printed shims with promising results in generating low spherical harmonic corrections. Experimental evaluations demonstrate feasibility of these 3D printed passive shims to induce target magnetic fields corresponding to second-order spherical harmonic, as evidenced by acquired B₀ maps. The electrically insulating properties of the printed shims eliminate the risk of eddy currents and heating, thus ensuring safety. The dimensional fabrication accuracy of the printed shims surpasses previous methods, enabling more precise and localized correction of subject-specific inhomogeneities. The findings highlight the potential of binder-jetted 3D printed passive shims in MRI shimming as a versatile and efficient solution for fabricating passive shims, with the potential to enhance the quality of MRI imaging while also being applicable to other types of Magnetic Resonance systems.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141090662","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}

{"title":"Experimental confirmation of the formation of collective modes of the magnetization motion of paramagnetic particles in dilute solutions due to spin exchange","authors":"K.M. Salikhov,&nbsp;M.M. Bakirov,&nbsp;I.T. Khairutdinov,&nbsp;R.B. Zaripov","doi":"10.1016/j.jmr.2024.107703","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107703","url":null,"abstract":"<div><p>Experimental confirmation of the manifestations of new spin exchange paradigm in EPR spectra of ¹⁴N nitroxide radical solutions is presented. It was shown that in the region of relatively low concentrations of radicals, the two side components of the spectrum have a mixed shape (the sum of the absorptive line and dispersive line). The dispersion contributions in these two lines have opposite signs. As the concentration of radicals increases, the contribution of dispersion passes through an extremum and in the region of maximum contribution of dispersion, the contribution of absorption to these two lines changes sign. In the region of high concentrations of radicals, when one homogeneously broadened line is practically observed, it turns out that these side components have resonant frequencies that do not coincide with the frequency of the center of gravity of the spectrum.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141083310","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}

{"title":"Low frequency signal detection via correlated Ramsey measurements","authors":"Santiago Oviedo-Casado ,&nbsp;Javier Prior ,&nbsp;Javier Cerrillo","doi":"10.1016/j.jmr.2024.107691","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107691","url":null,"abstract":"<div><p>The low frequency region of the spectrum is a challenging regime for quantum probes. We support the idea that, in this regime, performing Ramsey measurements carefully controlling the time at which each measurement is initiated is an excellent signal detection strategy. We use the Fisher information to demonstrate a high quality performance in the low frequency regime, compared to more elaborated measurement sequences, and to optimize the correlated Ramsey sequence according to any given experimental parameters, showing that correlated Ramsey rivals with state-of-the-art protocols, and can even outperform commonly employed sequences such as dynamical decoupling in the detection of low frequency signals. Contrary to typical quantum detection protocols for oscillating signals, which require adjusting the time separation between pulses to match the half period of the target signal, and consequently see their scope limited to signals whose period is shorter than the characteristic decoherence time of the probe, or to those protocols whose target is primarily static signals, the time-tagged correlated Ramsey sequence simultaneously tracks the amplitude and the phase information of the target signal, regardless of its frequency, which crucially permits correlating measurements in post-processing, leading to efficient spectral reconstruction.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1090780724000752/pdfft?md5=1d24603c786dd16956df5daf6da4888f&pid=1-s2.0-S1090780724000752-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141077937","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}

{"title":"Surface dielectric resonator for in vivo EPR measurements","authors":"Sergey V. Petryakov ,&nbsp;Maciej M. Kmiec ,&nbsp;Conner S. Ubert ,&nbsp;Victor B. Kassey ,&nbsp;Philip E. Schaner ,&nbsp;Periannan Kuppusamy","doi":"10.1016/j.jmr.2024.107690","DOIUrl":"10.1016/j.jmr.2024.107690","url":null,"abstract":"<div><p>This research report describes a novel surface dielectric resonator (SDR) with a flexible connector for <em>in vivo</em> electron paramagnetic resonance (EPR) spectroscopy. Contrary to the conventional cavity or surface loop-gap resonators, the newly developed SDR is constructed from a ceramic dielectric material, and it is tuned to operate at the L-band frequency band (1.15 GHz) in continuous-wave mode. The SDR is designed to be critically coupled and capable of working with both very lossy samples, such as biological tissues, and non-lossy materials. The SDR was characterized using electromagnetic field simulations, assessed for sensitivity with a B₁ field-perturbation method, and validated with tissue phantoms using EPR measurements. The results showed remarkably higher sensitivity in lossy tissue phantoms than the previously reported multisegment surface-loop resonators. The new SDR can provide potential new insights for advancements in the application of <em>in vivo</em> EPR spectroscopy for biological measurements, including clinical oximetry.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140768112","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}

{"title":"Frame change technique for phase transient cancellation","authors":"Andrew Stasiuk ,&nbsp;Pai Peng ,&nbsp;Garrett Heller ,&nbsp;Paola Cappellaro","doi":"10.1016/j.jmr.2024.107688","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107688","url":null,"abstract":"<div><p>The precise control of complex quantum mechanical systems can unlock applications ranging from quantum simulation to quantum computation. Controlling strongly interacting many-body systems often relies on Floquet Hamiltonian engineering that is achieved by fast switching between Hamiltonian primitives via external control. For example, in our solid-state NMR system, we perform quantum simulation by modulating the natural Hamiltonian with control pulses. As the Floquet heating errors scale with the interpulse delay, <span><math><mrow><mi>δ</mi><mi>t</mi></mrow></math></span>, it is favorable to keep <span><math><mrow><mi>δ</mi><mi>t</mi></mrow></math></span> as short as possible, forcing our control pulses to be short duration and high power. Additionally, high-power pulses help to minimize undesirable evolution from occurring during the duration of the pulse. However, such pulses introduce an appreciable phase-transient control error, a form of unitary error. In this work, we detail our ability to diagnose the error, calibrate its magnitude, and correct it for <span><math><mrow><mi>π</mi><mo>/</mo><mn>2</mn></mrow></math></span>-pulses of arbitrary phase. We demonstrate the improvements gained by correcting for the phase transient error, using a method which we call the “frame-change technique”, in a variety of experimental settings of interest. Given that the correction mechanism adds no real control overhead, we recommend that any resonance probe be checked for these phase transient control errors, and correct them using the frame-change technique.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140650734","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}

{"title":"NMR insights into β-Lactamase activity of UVI31+ Protein from Chlamydomonas reinhardtii","authors":"Ashok K. Rout ,&nbsp;Saurabh Gautam ,&nbsp;Vipin Kumar Mishra ,&nbsp;Mandar Bopardikar ,&nbsp;Budheswar Dehury ,&nbsp;Himanshu Singh","doi":"10.1016/j.jmr.2024.107689","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107689","url":null,"abstract":"<div><p>β-Lactamases (EC 3.5.2.6) confer resistance against β-lactam group-containing antibiotics in bacteria and higher eukaryotes, including humans. Pathogenic bacterial resistance against β-lactam antibiotics is a primary concern for potential therapeutic developments and drug targets. Here, we report putative β-lactamase activity, sulbactam binding (a β-lactam analogue) in the low μM affinity range, and site-specific interaction studies of a 14 kDa UV- and dark-inducible protein (abbreviated as UVI31+, a BolA homologue) from <em>Chlamydomonas reinhartii</em>. Intriguingly, the solution NMR structure of UVI31 + bears no resemblance to other known β-lactamases; however, the sulbactam binding is found at two sites rich in positively charged residues, mainly at the L2 loop regions and the N-terminus. Using NMR spectroscopy, ITC and MD simulations, we map the ligand binding sites in UVI31 + providing atomic-level insights into its β-lactamase activity. Current study is the first report on β-lactamase activity of UVI31+, a BolA analogue, from <em>C. reinhartii</em>. Furthermore, our mutation studies reveal that the active site serine-55 is crucial for β-lactamase activity.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140650688","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}

{"title":"A study of helium-3 nuclear magnetic relaxation mechanism in contact with 20 nm DyF3 nanoparticles","authors":"Adeliya Garaeva,&nbsp;Ekaterina Boltenkova,&nbsp;Kajum Safiullin ,&nbsp;Irina Romanova,&nbsp;Egor Alakshin","doi":"10.1016/j.jmr.2024.107672","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107672","url":null,"abstract":"<div><p>The spin kinetics of adsorbed and liquid ³He in contact with a mixture of LaF₃ (99.67 %) and DyF₃ (0.33 %) 20 nm powders at temperatures of 1.5–4.2 K in magnetic fields up to 505<!--> <!-->mT was studied by pulsed nuclear magnetic resonance (NMR). Two-component of nuclear magnetic relaxation was observed in the experiment and theoretical relaxation model was proposed. The possible explanation of this phenomena can be carried out by a model that consider the exchange of magnetization of helium-3 nuclei located in the adsorbed layer and in the bulk of the liquid. The proposed relaxation model can be applied to other systems with the strong influence of adsorbed layer.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140631711","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}

{"title":"Optimization of RF coil geometry for NMR/MRI applications using a genetic algorithm","authors":"Techit Tritrakarn ,&nbsp;Masato Takahashi ,&nbsp;Tetsuji Okamura","doi":"10.1016/j.jmr.2024.107685","DOIUrl":"https://doi.org/10.1016/j.jmr.2024.107685","url":null,"abstract":"<div><p>A simulation method that employs a genetic algorithm (GA) for optimizing radio frequency (RF) coil geometry is developed to maximize signal intensity in nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) applications. NMR/MRI has a wide range of applications, including medical imaging, and chemical and biological analysis to investigate the structure, dynamics, and interactions of molecules. However, NMR suffers from inherently low signal intensity, which depends on factors related to RF coil geometry. The investigation of coil geometry is crucial for improving signal intensity, leading to a reduction in the number of scans and a shorter total scan time. We have explored a better optimization method by modifying RF coil geometry to maximize signal intensity. The RF coil geometry comprises wire elements, each of which is a small vector representing the current flow, and GA chooses some of the prepared wire elements for optimization. The optimization of a substrate coil with a surface perpendicular to a static field was demonstrated for single-sided NMR system applications while considering various cylindrical sample diameters. A non-optimized and a GA-optimized substrate coil were compared through simulation and experiment to confirm the performance of the GA simulation. The maximum error between simulation and experiment was below 5%, with an average of less than 3%, confirming simulation reliability. The results indicated that the GA improved signal intensity by approximately 10% and reduced the necessary total scan time by around 20%. Finally, we explain the limitations and explore other potential applications of this GA-based simulation method.</p></div>","PeriodicalId":16267,"journal":{"name":"Journal of magnetic resonance","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140558167","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}