Measurements of Long-Range Homonuclear Coupling Constants

Mahi, L.; Duplan, J.C.

doi:10.1002/(sici)1097-458x(199706)35:6<379::aid-omr97>3.0.co;2-k

Cited by 5 publications

(5 citation statements)

References 1 publication

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“…Molecular species in H2O/D2O mixture: In the residual water, there are mainly three molecular species such as H2O, D2O and HDO in the solution 7 . The dynamic reaction among H2O, HDO and D2O can be expressed by the following equation [8][9][10][11] . (1) In the case of H2O/D2O mixture, H2O is added to D2O solution containing residual water.…”

Section: Results Related To the Traces And The Characteristics Of Thementioning

confidence: 99%

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Observation of Triplet Traces Obtained with Inversion Recovery Method in Both Residual Water- and H2O/D2O-Albumin Mixture by Using 400 MHz Proton NMR

Yılmaz¹,

Zengin²,

Korunur³

2013

Asian J. Chem.

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H 2 O/D 2 O mixtures are being used as solvent for proteins and some other chemical compounds 1-7 . In the mixture of H 2 O and D 2 O, there are three molecular species H 2 O, D 2 O and HDO in a dynamic equilibrium 8,9 . However, NMR spectrum of the mixture shows a single line at all static magnetic fields. Accordingly, the studies involving such solvents are mainly based on this single spectrum of water. The interpretation of the spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation data in H 2 O/ D 2 O mixture is known to be difficult 8,9 . The analysis of the equilibrium data among H 2 O, D 2 O and HDO was also reported to be difficult 10 . On the other hand, the small spin-spin splittings of H 2 O signal by deuterium (D) in H 2 O/D 2 O were studied by proton NMR for deuteriated water 10 . In addition, a triplet of 1 H NMR signals, which is the splitting of H 2 O signal by deuterium, was recently presented through a special free induction decay (FID) processing programme 11 . The splittings may be demonstrated further by the relaxation effects of the triplet components. The demonstration may be achieved by acquiring inversion recovery (IR) data of the triplet. It should contribute to the interpretation of NMR relaxation mechanisms NMR studies involving H2O/D2O mixtures are mainly based on a single spectrum of water. However, some recent papers have revealed the presence of an HDO triplet in H2O/D2O, which is caused by the splittings of H2O signal by deuterium (D). Observation of inversion recovery (IR) traces of this triplet should be very useful for analyzing relaxation data in such mixtures. In this work, in order to obtain the traces, inversion recovery signal intensities of residual water and a mixture of 0.10 H2O and 0.90 D2O were acquired versus a set of short delay times in the presence or absense of 0.2 g albumin. T1 and T2 curves of the same samples were also obtained by using different sets of much longer times for checking the effect of radiation damping on the traces. Experiments were carried out with a 400 MHz proton NMR spectrometer equipped with a topspin programme for relaxation measurements. Inversion recovery data of the traces and T1 curves were obtained with the inversion recovery method, while T2 curves were obtained with the Carr-Purcell-Meiboom-Gill method. Data was processed through an analysis programme of the topspin. Data showed that radiation damping is effectively reduced upon addition of albumin. Furthermore, the data of the residual water-and the mixture with albumin demonstrated the traces of the triplet at the initial part of a single inversion recovery line. Our results suggest that the splitting of water proton signal by deuterium can be detectable by the inversion recovery method for D2O-and the mixture containing albumin.

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Section: Results Related To the Traces And The Characteristics Of Thementioning

confidence: 99%

“…This eliminates the first choice to be the source of the traces. In addition, the traces are convenient to the study reporting small spin-spin splittings in H2O/D2O mixture 10 . They are also consistent with the previous one manifesting such a triplet by using a reconstitution programme 11 .…”

Section: Results Related To the Traces And The Characteristics Of Thementioning

confidence: 99%

Observation of Triplet Traces Obtained with Inversion Recovery Method in Both Residual Water- and H2O/D2O-Albumin Mixture by Using 400 MHz Proton NMR

Yılmaz¹,

Zengin²,

Korunur³

2013

Asian J. Chem.

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“…J doubling in the frequency domain is a simple and easy method for measuring coupling constants needed for the deconvolution. 15 Its modification was developed to deconvolve NMR signals in a very simple manner. Measurements obtained by J doubling and modified J doubling are identical.…”

Section: Convolution and Deconvolutionmentioning

confidence: 99%

New guide for first order multiplet analysis by modified J doubling in the frequency domain

Rı́o-Portilla¹,

Sánchez-Mendoza²,

Constantino-Castillo³

et al. 2004

Arkivoc

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Pattern recognition is extremely important for both structure elucidation and stereochemical studies as a means for the measurement of spin-spin coupling constants. Many treatises deal with the formation of splitting trees to create a pattern for a given set of spin-spin coupling constants. We present here a general systematic procedure to easily analyze first order multiplets in NMR spectroscopy. This method has the advantage of measuring coupling constants while deconvolving the signals at the same time using an extension of the modified J doubling in the frequency domain.

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“…Small coupling constants, particularly when they are on the order of the linewidths, are difficult to measure [18, 19, 20]. Inspection of adenosine NMR spectra does not provide any obvious support for long-range H2-H8 couplings.…”

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confidence: 99%

“…Small coupling constants, particularly when they are on the order of the line widths, are difficult to measure. − Inspection of adenosine NMR spectra does not provide any obvious support for long-range H2−H8 couplings. Therefore, we used quantum-mechanical calculations to predict a long-range coupling of −0.18 Hz. − However, these calculations also forecast several other nonvanishing couplings of H2 (to H3′, H5′, and H5′′) that were suspect (Figure S1A in the Supporting Information).…”

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confidence: 99%

Facilitated Assignment of Adenine H2 Resonances in Oligonucleotides Using Homonuclear Long-Range Couplings

2009

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NMR structural studies of nucleic acids require a near complete and unambiguous assignment of the proton resonances. This includes the adenine H2 protons which, especially in B type DNA, are generally far from other protons rendering their assignment cumbersome. In both A and B type nucleic acid helices, the H2 protons are located in the minor grooves where they serve as useful monitors for binding [1]. The conventional assignment method, which relies on NOE's recorded in D 2 O solution, generally does not allow complete assignment of H2 resonances. In practice, these resonances are often assigned from their NOE to imino protons of A•U or A•T base pairs [2,3]. This requires that experiments are carried out in H 2 O and the presence of detectable imino protons whose exchange with the solvent is sufficiently slow. For adenine residues in unpaired regions, other strategies are needed. Oligonucleotides that are 13 C labeled allow magnetization transfer between H2 and H8 protons via common couplings to intervening 13 C nuclei [4,5]. However, this approach is hampered by fast relaxing carbons. Subsequently, triple resonance experiments using [ 13 C, 15 N] labeled oligonucleotides were developed to correlate H2 and H8 protons (H-> 15 N-> 13 C->H) [6,7].. Such schemes feature increased sensitivity but require labeled oligonucleotides and that experiments are recorded in H 2 O. The development of higher sensitivity NMR probes and the use of low artifact gradient enhanced experiments enabled the assignments of H2 and H8 protons at natural abundance using HMBC experiments in D 2 O [8]. This experiment relies on a common heteronuclear long range coupling of both H2 and H8 to C4. However, the inherently low sensitivity requires very long acquisition times and/or high sample concentrations. In D 2 O solution the adenine H2 resonances are readily identified since they appear as narrow singlets with long longitudinal and transverse relaxation times. The long T 1 value is often a nuisance because it limits the repetition rate in many NMR experiments. On the other hand long T 2 values permit the use of pulse sequences with longer durations, which aid detection of even small couplings. Long-range 6 bond homonuclear couplings have been previously reported for polycyclic aromatic systems. [22]. Therefore, we explored if there is a homonuclear coupling between H2 and H8 of adenine that could be exploited.Small coupling constants, particularly when they are on the order of the linewidths, are difficult to measure [18,19,20]. Inspection of adenosine NMR spectra does not provide any obvious support for long-range H2-H8 couplings. Therefore, we used quantum mechanical calculations to predict a long range coupling of -0.18 Hz [15]. However, these calculation also forecast several other non-vanished couplings of H2 to H3′, H5′ and H5″ which are suspect (Figure S1 A). In view of these results, experimental verification is clearly needed. The H2-H8 coupling was assessed using a long-range optimized COSY experiment of adenosine 5′-monophospha...

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Measurements of Long-Range Homonuclear Coupling Constants

Cited by 5 publications

References 1 publication

Observation of Triplet Traces Obtained with Inversion Recovery Method in Both Residual Water- and H2O/D2O-Albumin Mixture by Using 400 MHz Proton NMR

Observation of Triplet Traces Obtained with Inversion Recovery Method in Both Residual Water- and H2O/D2O-Albumin Mixture by Using 400 MHz Proton NMR

New guide for first order multiplet analysis by modified J doubling in the frequency domain

Facilitated Assignment of Adenine H2 Resonances in Oligonucleotides Using Homonuclear Long-Range Couplings

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