Pub Date : 2023-10-05DOI: 10.1007/s00723-023-01604-0
Lena Marie Funke, Alicia Lund, Hao Zhuang, Jeffrey A. Reimer
Magnetic resonance spectroscopies occupy a premier position within the chemical sciences by revealing structure and dynamics in molecules and solids associated with photosynthesis, enzymology, Alzheimer proteins, pharmaceuticals, catalysts, polymers, and electronic materials. Here, we review the recent literature contributions of NMR and EPR spectroscopy towards the study of metal–organic frameworks from 2017 to mid-2022. We organize the review around what we perceive to be the intellectual challenges in MOF research: structure, dynamics, synthesis, properties, and function.
{"title":"Metal–Organic Frameworks: Challenges Addressed via Magnetic Resonance Spectroscopy","authors":"Lena Marie Funke, Alicia Lund, Hao Zhuang, Jeffrey A. Reimer","doi":"10.1007/s00723-023-01604-0","DOIUrl":"10.1007/s00723-023-01604-0","url":null,"abstract":"<div><p>Magnetic resonance spectroscopies occupy a premier position within the chemical sciences by revealing structure and dynamics in molecules and solids associated with photosynthesis, enzymology, Alzheimer proteins, pharmaceuticals, catalysts, polymers, and electronic materials. Here, we review the recent literature contributions of NMR and EPR spectroscopy towards the study of metal–organic frameworks from 2017 to mid-2022. We organize the review around what we perceive to be the intellectual challenges in MOF research: structure, dynamics, synthesis, properties, and function.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00723-023-01604-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134976237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-05DOI: 10.1007/s00723-023-01622-y
Jamie S. Lawton, David E. Budil
Abstract Heisenberg spin exchange between nitroxide (Tempone) spin probes has been measured as a function of concentration in the aqueous phase of the hydrated ion exchange membrane Nafion 117. The observed fast-motional electron paramagnetic resonance spectra were analyzed in terms of the stochastic Liouville equation lineshape calculation of Freed and coworkers and the “new paradigm” for interpreting spin exchange effects proposed by Salikhov. Differences between the effective spin exchange measured from the spectrum by these methods are presented and compared, and indicate that dipolar interactions make a significant contribution to spin exchange in this system. In acidic Nafion membranes, the spin probes are deactivated over time, allowing simultaneous measurement of the decay kinetics and spin exchange as a function of paramagnetic probe concentration. Both these processes deviate from the behavior that would be expected from classical chemical kinetics in isotropic media. The results are discussed in terms of currently available models for diffusion and reaction in a percolation network.
{"title":"Heisenberg Spin Exchange Between Nitroxide Probes Diffusing in a Percolation Network","authors":"Jamie S. Lawton, David E. Budil","doi":"10.1007/s00723-023-01622-y","DOIUrl":"https://doi.org/10.1007/s00723-023-01622-y","url":null,"abstract":"Abstract Heisenberg spin exchange between nitroxide (Tempone) spin probes has been measured as a function of concentration in the aqueous phase of the hydrated ion exchange membrane Nafion 117. The observed fast-motional electron paramagnetic resonance spectra were analyzed in terms of the stochastic Liouville equation lineshape calculation of Freed and coworkers and the “new paradigm” for interpreting spin exchange effects proposed by Salikhov. Differences between the effective spin exchange measured from the spectrum by these methods are presented and compared, and indicate that dipolar interactions make a significant contribution to spin exchange in this system. In acidic Nafion membranes, the spin probes are deactivated over time, allowing simultaneous measurement of the decay kinetics and spin exchange as a function of paramagnetic probe concentration. Both these processes deviate from the behavior that would be expected from classical chemical kinetics in isotropic media. The results are discussed in terms of currently available models for diffusion and reaction in a percolation network.","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134976179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-04DOI: 10.1007/s00723-023-01620-0
Samantha L. Gies, Maxx H. Tessmer, Dara W. Frank, Jimmy B. Feix
{"title":"Site-Directed Spin Label EPR Studies of the Structure and Membrane Interactions of the Bacterial Phospholipase ExoU","authors":"Samantha L. Gies, Maxx H. Tessmer, Dara W. Frank, Jimmy B. Feix","doi":"10.1007/s00723-023-01620-0","DOIUrl":"https://doi.org/10.1007/s00723-023-01620-0","url":null,"abstract":"","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135590892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-27DOI: 10.1007/s00723-023-01619-7
David S. Cafiso
{"title":"Wayne Hubbell and the Path to Site-Directed Spin Labeling","authors":"David S. Cafiso","doi":"10.1007/s00723-023-01619-7","DOIUrl":"https://doi.org/10.1007/s00723-023-01619-7","url":null,"abstract":"","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135537524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-24DOI: 10.1007/s00723-023-01611-1
Valentina Vitali, Katrin Ackermann, Gregor Hagelueken, Bela E. Bode
Abstract Biomolecular applications of pulse dipolar electron paramagnetic resonance spectroscopy (PDS) are becoming increasingly valuable in structural biology. Site-directed spin labelling of proteins is routinely performed using nitroxides, with paramagnetic metal ions and other organic radicals gaining popularity as alternative spin centres. Spectroscopically orthogonal spin labelling using different types of labels potentially increases the information content available from a single sample. When analysing experimental distance distributions between two nitroxide spin labels, the site-specific rotamer information has been projected into the distance and is not readily available, and the contributions of individual labelling sites to the width of the distance distribution are not obvious from the PDS data. Here, we exploit the exquisite precision of labelling double-histidine (dHis) motifs with Cu II chelate complexes. The contribution of this label to the distance distribution widths in model protein GB1 has been shown to be negligible. By combining a dHis Cu II labelling site with cysteine-specific nitroxide labelling, we gather insights on the label rotamers at two distinct sites, comparing their contributions to distance distributions based on different in silico modelling approaches and structural models. From this study, it seems advisable to consider discrepancies between different in silico modelling approaches when selecting labelling sites for PDS studies.
脉冲偶极电子顺磁共振波谱(PDS)在结构生物学中的生物分子应用越来越有价值。蛋白质的定点自旋标记通常使用氮氧化物进行，顺磁性金属离子和其他有机自由基作为替代自旋中心越来越受欢迎。光谱正交自旋标记使用不同类型的标签潜在地增加了信息含量，从一个单一的样品。在分析两个氮氧化物自旋标记之间的实验距离分布时，特定位点的旋转体信息已经投射到距离中，并且不易获得，并且从PDS数据中可以看出，单个标记位点对距离分布宽度的贡献并不明显。在这里，我们利用Cu II螯合物标记双组氨酸(dHis)基序的精细精度。该标签对模型蛋白GB1的距离分布宽度的贡献已被证明可以忽略不计。通过将dHis Cu II标记位点与半胱氨酸特异性氮氧化物标记位点相结合，我们收集了两个不同位点的标记转子的见解，比较了它们对基于不同硅建模方法和结构模型的距离分布的贡献。从这项研究来看，在选择PDS研究的标记位点时，考虑不同硅片建模方法之间的差异似乎是可取的。
{"title":"Spectroscopically Orthogonal Labelling to Disentangle Site-Specific Nitroxide Label Distributions","authors":"Valentina Vitali, Katrin Ackermann, Gregor Hagelueken, Bela E. Bode","doi":"10.1007/s00723-023-01611-1","DOIUrl":"https://doi.org/10.1007/s00723-023-01611-1","url":null,"abstract":"Abstract Biomolecular applications of pulse dipolar electron paramagnetic resonance spectroscopy (PDS) are becoming increasingly valuable in structural biology. Site-directed spin labelling of proteins is routinely performed using nitroxides, with paramagnetic metal ions and other organic radicals gaining popularity as alternative spin centres. Spectroscopically orthogonal spin labelling using different types of labels potentially increases the information content available from a single sample. When analysing experimental distance distributions between two nitroxide spin labels, the site-specific rotamer information has been projected into the distance and is not readily available, and the contributions of individual labelling sites to the width of the distance distribution are not obvious from the PDS data. Here, we exploit the exquisite precision of labelling double-histidine (dHis) motifs with Cu II chelate complexes. The contribution of this label to the distance distribution widths in model protein GB1 has been shown to be negligible. By combining a dHis Cu II labelling site with cysteine-specific nitroxide labelling, we gather insights on the label rotamers at two distinct sites, comparing their contributions to distance distributions based on different in silico modelling approaches and structural models. From this study, it seems advisable to consider discrepancies between different in silico modelling approaches when selecting labelling sites for PDS studies.","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135924300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-24DOI: 10.1007/s00723-023-01613-z
Mikhail N. Uvarov, Denis S. Baranov, Danil A. Nevostruev, Natalia V. Kravets, Aina V. Kulikova, Dmitrii E. Utkin, Sergei A. Ponomarev, Maxim S. Kazantsev, Vladimir A. Zinoviev, Leonid V. Kulik
{"title":"Tetraazapyrene Functionalized Nitroxide Radical as Self-Deposited Functional Interlayer in Organic Solar Cells","authors":"Mikhail N. Uvarov, Denis S. Baranov, Danil A. Nevostruev, Natalia V. Kravets, Aina V. Kulikova, Dmitrii E. Utkin, Sergei A. Ponomarev, Maxim S. Kazantsev, Vladimir A. Zinoviev, Leonid V. Kulik","doi":"10.1007/s00723-023-01613-z","DOIUrl":"https://doi.org/10.1007/s00723-023-01613-z","url":null,"abstract":"","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135925832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-22DOI: 10.1007/s00723-023-01615-x
Evan R. McCarney, Robin Dykstra, Cameron G. Dykstra, Anthony FitzPatrick
Grading systems within the beef industry have created value along the entire product chain from the farm to the consumer. Carcases in the meat industry are typically graded into separate value brackets. However, most data collected on carcases is either subjective, unreliable or not practical to be obtained in the processing line. One of the main drivers of value is intramuscular fat (IMF), also know as marbling in beef. NMR is a proven tool for measuring the fat and oil content in foods but the meat industry provides particular challenges such as large samples, fast cycle time > 10/min, a specific measurement location, limited foot-print for the equipment, harsh environment, food safe materials, automation due to lack of labour force, and integration into data systems. While fat in meat has been measured previously, we have developed the technology to meet many of the above processing plant challenges. A unilateral NMR magnet and RF coil were designed and fabricated inhouse and integrated into a carcase handling rig. The complete system was tested in a processing plant over four weeks. The system was capable of measuring intramuscular fat at the industry standard accuracy of ± 1% IMF. We were able to measure at a rate of 4.2 carcases per minute.
{"title":"Automated Eating Quality Measurements on Lamb Carcases in a Processing Plant Using Unilateral NMR","authors":"Evan R. McCarney, Robin Dykstra, Cameron G. Dykstra, Anthony FitzPatrick","doi":"10.1007/s00723-023-01615-x","DOIUrl":"10.1007/s00723-023-01615-x","url":null,"abstract":"<div><p>Grading systems within the beef industry have created value along the entire product chain from the farm to the consumer. Carcases in the meat industry are typically graded into separate value brackets. However, most data collected on carcases is either subjective, unreliable or not practical to be obtained in the processing line. One of the main drivers of value is intramuscular fat (IMF), also know as marbling in beef. NMR is a proven tool for measuring the fat and oil content in foods but the meat industry provides particular challenges such as large samples, fast cycle time > 10/min, a specific measurement location, limited foot-print for the equipment, harsh environment, food safe materials, automation due to lack of labour force, and integration into data systems. While fat in meat has been measured previously, we have developed the technology to meet many of the above processing plant challenges. A unilateral NMR magnet and RF coil were designed and fabricated inhouse and integrated into a carcase handling rig. The complete system was tested in a processing plant over four weeks. The system was capable of measuring intramuscular fat at the industry standard accuracy of ± 1% IMF. We were able to measure at a rate of 4.2 carcases per minute.</p></div>","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136016533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-22DOI: 10.1007/s00723-023-01616-w
Aritro Sinha Roy, Jack H. Freed, Madhur Srivastava
{"title":"Differentiating Unimodal and Multimodal Distributions in Pulsed Dipolar Spectroscopy Using Wavelet Transforms","authors":"Aritro Sinha Roy, Jack H. Freed, Madhur Srivastava","doi":"10.1007/s00723-023-01616-w","DOIUrl":"https://doi.org/10.1007/s00723-023-01616-w","url":null,"abstract":"","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136016377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-19DOI: 10.1007/s00723-023-01612-0
Magdalena Schumacher, Christian Bamann, Heinz-Jürgen Steinhoff
Abstract The light-gated dimeric cation channel channelrhodopsin-2 (ChR2) is one of the most important optogenetic tools. Upon light activation ChR2 undergoes conformational changes, the most prominent ones include a movement of transmembrane helix B. In the present work, we apply time resolved continuous wave EPR spectroscopy to follow spectral changes of a spin label bound to position C79 located in helix B. We observed an increase of the motional freedom of the spin label side chain in illuminated ChR2. The recovery of the underlying light-induced conformational change in the dark is correlated with the recovery of the P480 state of ChR2. The observed conformational changes might be thus key elements responsible for desensitizing the channel for cation conduction.
{"title":"Time-Resolved EPR Spectroscopy of Channelrhodopsin-2 Helix B Movements","authors":"Magdalena Schumacher, Christian Bamann, Heinz-Jürgen Steinhoff","doi":"10.1007/s00723-023-01612-0","DOIUrl":"https://doi.org/10.1007/s00723-023-01612-0","url":null,"abstract":"Abstract The light-gated dimeric cation channel channelrhodopsin-2 (ChR2) is one of the most important optogenetic tools. Upon light activation ChR2 undergoes conformational changes, the most prominent ones include a movement of transmembrane helix B. In the present work, we apply time resolved continuous wave EPR spectroscopy to follow spectral changes of a spin label bound to position C79 located in helix B. We observed an increase of the motional freedom of the spin label side chain in illuminated ChR2. The recovery of the underlying light-induced conformational change in the dark is correlated with the recovery of the P480 state of ChR2. The observed conformational changes might be thus key elements responsible for desensitizing the channel for cation conduction.","PeriodicalId":469,"journal":{"name":"Applied Magnetic Resonance","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135014283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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