{"title":"魔角自旋核磁共振下的低功率华尔兹解耦。","authors":"Luzian Thomas, Matthias Ernst","doi":"10.5194/mr-5-153-2024","DOIUrl":null,"url":null,"abstract":"<p><p>Heteronuclear low-power decoupling using the solution-state wideband alternating-phase low-power technique for zero-residual splitting (WALTZ) sequences has become quite popular in solid-state protein NMR and seems to work well. However, there are no systematic studies that characterize these sequences under magic-angle spinning (MAS) and give recommendations on which parameter should be used. We have studied in detail the use of WALTZ-16 and WALTZ-64 as low-power decoupling sequences under 100 kHz MAS by characterizing the resonance conditions analytically using numerical simulations and experiments on model substances. The recoupling heteronuclear resonance conditions between the modulation frequency of the sequences and the MAS frequency is the most important feature. Pulse lengths corresponding to areas with vanishing first-order heteronuclear recoupling are good candidates for efficient decoupling. We have characterized two such conditions which can be defined using the nutation frequency of the radio frequency (RF) field ( <math> <mrow><msub><mi>ν</mi> <mn>1</mn></msub> </mrow> </math> ) and the spinning frequency ( <math> <mrow><msub><mi>ν</mi> <mi>r</mi></msub> </mrow> </math> ) by <math> <mrow><msub><mi>ν</mi> <mn>1</mn></msub> <mo>=</mo> <msub><mi>ν</mi> <mi>r</mi></msub> <mo>/</mo> <mn>10</mn></mrow> </math> and <math> <mrow><msub><mi>ν</mi> <mn>1</mn></msub> <mo>=</mo> <mn>2</mn> <msub><mi>ν</mi> <mi>r</mi></msub> <mo>/</mo> <mn>5</mn></mrow> </math> , which both lead to narrow lines and are stable against RF-field variations and chemical-shift offsets. More such conditions might exist but were not investigated here.</p>","PeriodicalId":93333,"journal":{"name":"Magnetic resonance (Gottingen, Germany)","volume":"5 2","pages":"153-166"},"PeriodicalIF":0.0000,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12178133/pdf/","citationCount":"0","resultStr":"{\"title\":\"Low-power WALTZ decoupling under magic-angle spinning NMR.\",\"authors\":\"Luzian Thomas, Matthias Ernst\",\"doi\":\"10.5194/mr-5-153-2024\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Heteronuclear low-power decoupling using the solution-state wideband alternating-phase low-power technique for zero-residual splitting (WALTZ) sequences has become quite popular in solid-state protein NMR and seems to work well. However, there are no systematic studies that characterize these sequences under magic-angle spinning (MAS) and give recommendations on which parameter should be used. We have studied in detail the use of WALTZ-16 and WALTZ-64 as low-power decoupling sequences under 100 kHz MAS by characterizing the resonance conditions analytically using numerical simulations and experiments on model substances. The recoupling heteronuclear resonance conditions between the modulation frequency of the sequences and the MAS frequency is the most important feature. Pulse lengths corresponding to areas with vanishing first-order heteronuclear recoupling are good candidates for efficient decoupling. We have characterized two such conditions which can be defined using the nutation frequency of the radio frequency (RF) field ( <math> <mrow><msub><mi>ν</mi> <mn>1</mn></msub> </mrow> </math> ) and the spinning frequency ( <math> <mrow><msub><mi>ν</mi> <mi>r</mi></msub> </mrow> </math> ) by <math> <mrow><msub><mi>ν</mi> <mn>1</mn></msub> <mo>=</mo> <msub><mi>ν</mi> <mi>r</mi></msub> <mo>/</mo> <mn>10</mn></mrow> </math> and <math> <mrow><msub><mi>ν</mi> <mn>1</mn></msub> <mo>=</mo> <mn>2</mn> <msub><mi>ν</mi> <mi>r</mi></msub> <mo>/</mo> <mn>5</mn></mrow> </math> , which both lead to narrow lines and are stable against RF-field variations and chemical-shift offsets. 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引用次数: 0
摘要
利用溶液态宽带交变相低功率技术进行零残留分裂(华尔兹)序列的异核低功率解耦在固态蛋白质核磁共振中已经得到了广泛的应用,并取得了良好的效果。然而,目前还没有系统的研究来描述这些序列在魔角旋转(MAS)下的特征,并给出应该使用哪些参数的建议。我们详细研究了在100 kHz MAS下使用华尔兹-16和华尔兹-64作为低功率解耦序列,通过对模型物质的数值模拟和实验分析表征共振条件。序列调制频率与MAS频率之间的重耦合异核共振条件是其最重要的特征。一阶异核耦合消失区域对应的脉冲长度是有效解耦的良好候选者。我们用射频场(RF)的章动频率(ν 1)和自旋频率(ν r)分别定义了这两种条件:ν 1 = ν r / 10和ν 1 = 2 ν r / 5,这两种条件都导致谱线变窄,并且对RF场变化和化学位移偏移都是稳定的。可能存在更多这样的情况,但这里没有进行调查。
Low-power WALTZ decoupling under magic-angle spinning NMR.
Heteronuclear low-power decoupling using the solution-state wideband alternating-phase low-power technique for zero-residual splitting (WALTZ) sequences has become quite popular in solid-state protein NMR and seems to work well. However, there are no systematic studies that characterize these sequences under magic-angle spinning (MAS) and give recommendations on which parameter should be used. We have studied in detail the use of WALTZ-16 and WALTZ-64 as low-power decoupling sequences under 100 kHz MAS by characterizing the resonance conditions analytically using numerical simulations and experiments on model substances. The recoupling heteronuclear resonance conditions between the modulation frequency of the sequences and the MAS frequency is the most important feature. Pulse lengths corresponding to areas with vanishing first-order heteronuclear recoupling are good candidates for efficient decoupling. We have characterized two such conditions which can be defined using the nutation frequency of the radio frequency (RF) field ( ) and the spinning frequency ( ) by and , which both lead to narrow lines and are stable against RF-field variations and chemical-shift offsets. More such conditions might exist but were not investigated here.