• Analytical Science and Technology
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• v.11 no.1
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• pp.73-78
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• 1998

The reverse detection heteronuclear multiple quantum coherence, HMQC study of metcyano complex of horse myoglobin(MbCN) has provided the complete assignment of hyperfine shifted resonances of heme carbons attached with proton(s). The application of HMQC experiment to the paramagnetic low-spin MbCN gives clear $^1H$ and $^{13}C$ coherences for the paramagnetic amino acid residues as well as heme side chains, and can be extended to the low-spin paramagnetic hemoprotein derivative for the assignment of natural abundance $^{13}C$ resonances. This assignment strategy can avoid possible ambiguities that may result from the sole utilization of $^1H$ nuclear Overhauser effect for the assignment of heme $^1H$ signals resonating in the diamagnetic region. The resulting 2,4-vinyl ${\alpha}$-carbons and 7-propionate ${\beta}$-carbon follow anomalous anti-Curie behavior, and are indicative of incoplanarity with heme plane. Magnetic/electronic asymmetry of heme induced by proximal histidine(His) makes spread that the hyperfine shifted heme carbon resonances over the range of 250 ppm at $25^{\circ}C$. These heme carbon resonances would be the much more sensitive probe than those of proton resonances in analyzing the nature of heme electronic structure of myoglobin.

• BMB Reports
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• v.28 no.5
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• pp.433-436
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• 1995

In order to assign NMR signals, conditions for the specific labeling of cytochrome $c_3$ of D. vulgaris Miyazaki F through the culture in a minimal medium were established. Phenylalanine residue was specifically deuterated at more than 85% efficiency. Cytochrome $c_3$ has two phenylalanine residues. The signals of one phenylalane were missing and this was tentatively assigned to Phe20.

• Analytical Science and Technology
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• v.18 no.1
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• pp.85-88
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• 2005

Antiphase character of cross peaks in long-range COSY is modulated by changing the fixed delay time and used to assign diastereotopic methylene protons on rigid systems which could produce unpredictable NOE phenomena because of complicate coupling spins.

• Archives of Pharmacal Research
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• v.14 no.2
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• pp.160-164
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• 1991

The existence in nature of two isomers of 28-nortriterpenes is known. One is normal D/E cis form and the other is $17\alpha$-hydrogen D/E trans form. Since the latter cannot exist with ring D in the chair conformation, the chiroptical method is not applicable to determination of the absolute configuration. The stereochemical assignment would now be made by NMR data. Confirmation of this view could be provided by the synthesis of $3\beta, 21\beta-{dihydroxy-16-keto-28-nor-17}\alpha, \;18\beta-{olean-12-ene}$ as a model compound.

• Natural Product Sciences
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• v.9 no.4
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• pp.220-222
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• 2003

Two new abietane diterpenes with rearranged skeleton; aegyptinol and aegyptinone C; have been isolated and identified for the first time from the anti-microbial petroleum ether extract of the roots of Salvia aegyptiaca L. Their chemical structures have been elucidated by interpretation of the detailed 1D-and 2D-NMR spectra, as well as other spectroscopic tools. In addition, full assignment of $^{13}C-NMR$ of aegyptinone B was also conducted for the first time.

• Archives of Pharmacal Research
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• v.17 no.4
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• pp.284-286
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• 1994

A guaian type sesquiterpene, torilin, was isolated from the hexane extract of the fruits of Torilis japonica. The $^1H{\;}and{\;}^{13}C-sinals$ of this compound have been fully assigned utilizing $^1H-^1H$ COSY, HMQC, and HMBC experiments.

• Natural Product Sciences
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• v.9 no.2
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• pp.49-51
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• 2003

The underground part of Rosa rugosa Thunb. has been used in Korean folk medicine for treating diabetes. The $^{1}H-NMR$ signal of procyanidin B3 isolated from Rosa rugosa was fully assigned by utilizing $^{1}H-^{1}H$ COSY. Procyandin B3 showed a moderate inhibitory activity against HIV-1 protease.

• Journal of the Korean Magnetic Resonance Society
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• v.26 no.4
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• pp.66-70
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• 2022

Protein structure determination using NMR spectroscopy requires a suite of heteronuclear 3-D NMR experiments that can take a couple of weeks for completion. During the experiments, protein samples may suffer from slow degradation due to co-purifying proteases, which complicates and slows down the assignment procedure. Here we describe a practical protocol to avoid unwanted proteolysis during the experiment.

• Archives of Pharmacal Research
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• v.14 no.3
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• pp.237-241
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• 1991

The tautomerism in 3-phenyl-4-arylazo-5-isoxazolones 1 was examined by $^1H-NMR$ spectra of $^15N-labeled$ compound and by HMO method. Both spectra data $(^1H-NMR\;and\;IR)$ and bonding energies are in support of the assignment of the hydrazone structure to such compounds. It is further shown that intermolecular and intramolecular hydrogen bondings favor the hydrazone tautomer.

• Journal of the Korean Magnetic Resonance Society
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• v.27 no.2
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• pp.10-15
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• 2023

The Strain-Promoted Azide-Alkyne Cycloaddition (SPAAC) is a powerful method for synthesizing triazoles, even under physiological conditions, without a copper catalyst. This technique provides an efficient means for everyone to synthesize complex triazole derivatives rapidly. In order to investigate the configuration of triazole derivatives using bicyclo[6.1.0.]-nonyne (BCN) and chiral azide, it is necessary to employ the 2D NMR. Both 1D and 2D NMR (COSY, HSQC, ¹⁵N HMBC) are used to analyze the complex triazole product containing cyclooctyne, a diastereomeric product. The stereometric difference of the proton bonded to the same carbon is determined through the HSQC assignment. The intriguing splitting pattern of carbon resonances also reveals their diastereomeric configuration and will aid in further research based on physiological knowledge.