Magnetic Resonance in Chemistry最新文献

{"title":"Challenges and opportunities in elucidating the structures of biofilm exopolysaccharides: A case study of the Pseudomonas aeruginosa exopolysaccharide called Pel","authors":"Kristen Amyx-Sherer,&nbsp;Courtney Reichhardt","doi":"10.1002/mrc.5405","DOIUrl":"10.1002/mrc.5405","url":null,"abstract":"<p>Biofilm formation protects bacteria from antibiotic treatment and host immune responses, making biofilm infections difficult to treat. Within biofilms, bacterial cells are entangled in a self-produced extracellular matrix that typically includes exopolysaccharides. Molecular-level descriptions of biofilm matrix components, especially exopolysaccharides, have been challenging to attain due to their complex nature and lack of solubility and crystallinity. Solid-state nuclear magnetic resonance (NMR) has emerged as a key tool to determine the structure of biofilm matrix exopolysaccharides without degradative sample preparation. In this review, we discuss challenges of studying biofilm matrix exopolysaccharides and opportunities to develop solid-state NMR approaches to study these generally intractable materials. We specifically highlight investigations of the exopolysaccharide called Pel made by the opportunistic pathogen, <i>Pseudomonas aeruginosa</i>. We provide a roadmap for determining exopolysaccharide structure and discuss future opportunities to study such systems using solid-state NMR. The strategies discussed for elucidating biofilm exopolysaccharide structure should be broadly applicable to studying the structures of other glycans.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 5","pages":"361-369"},"PeriodicalIF":2.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71424853","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":"Simulation of oriented NMR spectra: Combining molecular dynamics and chemical shift tensor calculations","authors":"Ulrich Sternberg,&nbsp;Raiker Witter","doi":"10.1002/mrc.5403","DOIUrl":"10.1002/mrc.5403","url":null,"abstract":"<p>Solid state NMR is widely used to study the orientation and other structural features of proteins and peptides in lipid bilayers. Using data obtained by PISEMA (Polarization Inversion Spin Exchange at Magic Angle) experiments, periodic spectral patterns arise from well-aligned α-helical molecules. Significant problems in the interpretation of PISEMA spectra may arise for systems that do not form perfectly defined secondary structures, like α-helices, or the signal pattern is disturbed by molecular motion. Here, we present a new method that combines molecular dynamics simulation with tensorial orientational constraints (MDOC) and chemical shift tensor calculations for the simulation and interpretation of PISEMA-like spectra. The calculations include the spectra arising from non α-helical molecules and molecules with non-uniform intrinsic mobility. In a first step, dipolar or quadrupolar interaction tensors drive molecular rotations and reorientations to obtain the proper mean values as observed in corresponding NMR experiments. In a second step, the coordinate snapshots of the MDOC simulations are geometry optimized with the isotropic ¹⁵N chemical shifts as constraints using Bond Polarization Theory (BPT) to provide reliable ¹⁵N CS tensor data. The averaged dipolar ¹H-¹⁵N couplings and the <i>δ</i>_<i>zz</i> tensor components can then be combined to simulate PISEMA patterns. We apply this method to the ß-helical peptide gramicidin A (gA) and demonstrate that this method enables the assignment of most PISEMA resonances. In addition, MDOC simulations provide local order parameters for the calculated sites. These local order parameters reveal large differences in backbone mobility between L- and D-amino acids of gA.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 3","pages":"125-144"},"PeriodicalIF":2.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5403","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54229805","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":"Molecular precursors to produce para-hydrogen enhanced metabolites at any field","authors":"Anil P. Jagtap,&nbsp;Salvatore Mamone,&nbsp;Stefan Glöggler","doi":"10.1002/mrc.5402","DOIUrl":"10.1002/mrc.5402","url":null,"abstract":"<p>Enhancing magnetic resonance signal via hyperpolarization techniques enables the real-time detection of metabolic transformations even in vivo. The use of para-hydrogen to enhance ¹³C-enriched metabolites has opened a rapid pathway for the production of hyperpolarized metabolites, which usually requires specialized equipment. Metabolite precursors that can be hyperpolarized and converted into metabolites at any given field would open up opportunities for many labs to make use of this technology because already existing hardware could be used. We report here on the complete synthesis and hyperpolarization of suitable precursor molecules of the side-arm hydrogenation approach. The better accessibility to such side-arms promises that the para-hydrogen approach can be implemented in every lab with existing two channel NMR spectrometers for ¹H and ¹³C independent of the magnetic field.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 12","pages":"674-680"},"PeriodicalIF":2.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5402","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41204557","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":"Low-field, not low quality: 1D simplification, selective detection, and heteronuclear 2D experiments for improving low-field NMR spectroscopy of environmental and biological samples","authors":"Katelyn Downey,&nbsp;Wolfgang Bermel,&nbsp;Ronald Soong,&nbsp;Daniel H. Lysak,&nbsp;Kiera Ronda,&nbsp;Katrina Steiner,&nbsp;Peter M. Costa,&nbsp;William W. Wolff,&nbsp;Venita Decker,&nbsp;Falko Busse,&nbsp;Benjamin Goerling,&nbsp;Agnes Haber,&nbsp;Myrna J. Simpson,&nbsp;Andre J. Simpson","doi":"10.1002/mrc.5401","DOIUrl":"10.1002/mrc.5401","url":null,"abstract":"<p>Understanding environmental change is challenging and requires molecular-level tools to explain the physicochemical phenomena behind complex processes. Nuclear magnetic resonance (NMR) spectroscopy is a key tool that provides information on both molecular structures and interactions but is underutilized in environmental research because standard “high-field” NMR is financially and physically inaccessible for many and can be overwhelming to those outside of disciplines that routinely use NMR. “Low-field” NMR is an accessible alternative but has reduced sensitivity and increased spectral overlap, which is especially problematic for natural, heterogeneous samples. Therefore, the goal of this study is to investigate and apply innovative experiments that could minimize these challenges and improve low-field NMR analysis of environmental and biological samples. Spectral simplification (JRES, PSYCHE, singlet-only, multiple quantum filters), selective detection (GEMSTONE, DREAMTIME), and heteronuclear (reverse and CH₃/CH₂/CH-only HSQCs) NMR experiments are tested on samples of increasing complexity (amino acids, spruce resin, and intact water fleas) at-high field (500 MHz) and at low-field (80 MHz). A novel experiment called Doubly Selective HSQC is also introduced, wherein ¹H signals are selectively detected based on the ¹H and ¹³C chemical shifts of ¹H–¹³C J-coupled pairs. The most promising approaches identified are the selective techniques (namely for monitoring), and the reverse and CH₃-only HSQCs. Findings ultimately demonstrate that low-field NMR holds great potential for biological and environmental research. The multitude of NMR experiments available makes NMR tailorable to nearly any research need, and low-field NMR is therefore anticipated to become a valuable and widely used analytical tool moving forward.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 5","pages":"345-360"},"PeriodicalIF":2.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41100154","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":"Studying the interaction of glycans with intact virions and virus-like particles by ligand-observed NMR spectroscopy","authors":"Thomas Haselhorst","doi":"10.1002/mrc.5399","DOIUrl":"10.1002/mrc.5399","url":null,"abstract":"<p>Virus-glycan interactions play a crucial role in the infection process of many viruses. NMR spectroscopy has emerged as a powerful tool for studying these interactions at the molecular level. In this article, we review several published papers and reports that have highlighted the application of NMR spectroscopy in understanding the complex questions of how viruses engage with and bind to receptor glycans. The use of saturation transfer difference (STD) NMR spectroscopy has demonstrated itself as highly advantageous in investigating the interaction between glycans and intact virions or virus-like particles (VLPs). The broad NMR signal linewidth of virions and VLPs allows efficient saturation without affecting the glycan signals. The advantage of this approach is that the viral capsid environment in protein organization and function is not ignored and therefore provides a more biologically relevant model for exploring the interactions between the virus and the host cell glycans. We will review some examples of using NMR spectroscopy to study influenza cell tropism, rotaviruses, and noroviruses.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 5","pages":"337-344"},"PeriodicalIF":2.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5399","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41137387","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":"Characterization of fatty acid forms using benchtop NMR in omega-3 oil supplements","authors":"Carla Remy,&nbsp;Saïda Danoun,&nbsp;Mathieu Delample,&nbsp;Cameron Morris,&nbsp;Véronique Gilard,&nbsp;Stéphane Balayssac","doi":"10.1002/mrc.5398","DOIUrl":"10.1002/mrc.5398","url":null,"abstract":"<p>Omega-3 fatty acid supplements, such as fish oil and plant-based oils, have gained popularity because of their potential health benefits. However, the quality and composition of these supplements can vary widely, particularly in terms of the two main forms of omega-3 fatty acids: triacylglycerols (TAGs) and ethyl esters (EEs). TAGs are the natural form found in fish oil but are prone to oxidation, whereas EEs are more stable but less well absorbed by the body. Differentiating between these forms is crucial for assessing the efficacy and tolerance of omega-3 supplements. This article describes a novel approach to differentiate between TAG and EE forms of omega-3 fatty acids in dietary supplements, utilizing a 60-MHz benchtop nuclear magnetic resonance (NMR) spectrometer. The proposed method using ¹H and ¹H-¹H COSY NMR provides a quick and accurate approach to screen the forms of omega-3 fatty acids and evaluate their ratios. The presence of diacylglycerol (DAGs) in some supplements was also highlighted by this method and adds some information about the process used (i.e., esterification/enrichment). The affordability and user-friendliness of benchtop NMR equipment make this method feasible for food processing companies or quality control laboratories. In this study, 24 oil supplements were analyzed using NMR analysis in order to demonstrate the potential of this method for the differentiation of TAG and EE forms in omega-3 supplements.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 5","pages":"328-336"},"PeriodicalIF":2.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5398","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41137592","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":"Reaction monitoring via benchtop nuclear magnetic resonance spectroscopy: A practical comparison of on-line stopped-flow and continuous-flow sampling methods","authors":"Tristan Maschmeyer,&nbsp;David J. Russell,&nbsp;José G. Napolitano,&nbsp;Jason E. Hein","doi":"10.1002/mrc.5395","DOIUrl":"10.1002/mrc.5395","url":null,"abstract":"<p>The ability for nuclear magnetic resonance (NMR) spectroscopy to provide quantitative, structurally rich information makes this spectroscopic technique an attractive reaction monitoring tool. The practicality of NMR for this type of analysis has only increased in the recent years with the influx of commercially available benchtop NMR instruments and compatible flow systems. In this study, we aim to compare ¹⁹F NMR reaction profiles acquired under both <i>on-line</i> continuous-flow and stopped-flow sampling methods, with modern benchtop NMR instrumentation, and two reaction systems: a homogeneous imination reaction and a biphasic activation of a carboxylic acid to acyl fluoride. Reaction trends with higher data density can be acquired with <i>on-line</i> continuous-flow analyses, and this work highlights that representative reaction trends can be acquired without any correction when monitoring resonances with a shorter spin–lattice relaxation time (<i>T</i>₁), and with the used flow conditions. <i>On-line</i> stopped-flow analyses resulted in representative reaction trends in all cases, including the monitoring of resonances with a long <i>T</i>₁, without the need of any correction factors. The benefit of easier data analysis, however, comes with the cost of time, as the fresh reaction solution must be flowed into the NMR system, halted, and time must be provided for spins to become polarized in the instrument's external magnetic field prior to spectral measurement. Results for one of the reactions were additionally compared with the use of a high-field NMR.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 4","pages":"310-322"},"PeriodicalIF":2.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5395","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41132320","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":"J-filter: An experiment to simplify and isolate specific signals in 1H NMR spectra of complex mixtures based on scalar coupling constants","authors":"Karen V. Góñez,&nbsp;Juan Suárez García,&nbsp;F. Javier Sardina,&nbsp;Yolanda Pazos,&nbsp;Ángela Saá,&nbsp;Manuel Martín−Pastor","doi":"10.1002/mrc.5396","DOIUrl":"https://doi.org/10.1002/mrc.5396","url":null,"abstract":"<p>One-dimensional selective NMR experiments relying on a J-filter element are proposed to isolate specific signals in crowded ¹H spectral regions. The J-filter allows the edition or filtering of signals in a region of interest of the spectrum by exploiting the specific values of their ¹H-¹H coupling constants and certain parameters of protons coupled to them that appear in less congested parts of the spectrum (chemical shifts and coupling constants). The new experiments permitted the isolation of specific peaks of phytosterol components in a sample obtained from a liquid nutraceutical recommended for lowering blood cholesterol levels in regions with complete overlap in the ¹H spectrum.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 11","pages":"615-622"},"PeriodicalIF":2.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5396","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50138156","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":"Quantitative NMR using water as internal calibrant","authors":"Bosong Xiang","doi":"10.1002/mrc.5394","DOIUrl":"10.1002/mrc.5394","url":null,"abstract":"<p>A new quantitative nuclear magnetic resonance (qNMR) method, called qNMRw, using water as the internal calibrant has been developed. Its principles, procedures, calculations, and test results are presented here. It is shown to avoid the difficulties created by moisture present in other reference materials. High precision and accuracy can be achieved with qNMRw. The method can be used for analyzing technical materials, herbicide formulation products, and other types of chemical samples. It can also be used to measure the purity and concentration of materials to be used as quantitation calibrants.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"61 11","pages":"565-573"},"PeriodicalIF":2.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5394","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10309461","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":"Charting the solid-state NMR signals of polysaccharides: A database-driven roadmap","authors":"Wancheng Zhao,&nbsp;Debkumar Debnath,&nbsp;Isha Gautam,&nbsp;Liyanage D. Fernando,&nbsp;Tuo Wang","doi":"10.1002/mrc.5397","DOIUrl":"10.1002/mrc.5397","url":null,"abstract":"<p>Solid-state nuclear magnetic resonance (ssNMR) measurements of intact cell walls and cellular samples often generate spectra that are difficult to interpret due to the presence of many coexisting glycans and the structural polymorphism observed in native conditions. To overcome this analytical challenge, we present a statistical approach for analyzing carbohydrate signals using high-resolution ssNMR data indexed in a carbohydrate database. We generate simulated spectra to demonstrate the chemical shift dispersion and compare this with experimental data to facilitate the identification of important fungal and plant polysaccharides, such as chitin and glucans in fungi and cellulose, hemicellulose, and pectic polymers in plants. We also demonstrate that chemically distinct carbohydrates from different organisms may produce almost identical signals, highlighting the need for high-resolution spectra and validation of resonance assignments. Our study provides a means to differentiate the characteristic signals of major carbohydrates and allows us to summarize currently undetected polysaccharides in plants and fungi, which may inspire future investigations.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":"62 4","pages":"298-309"},"PeriodicalIF":2.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5397","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41122035","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}