Determination of the 14N quadrupole coupling tensors in a single crystal of l-histidine hydrochloride monohydrate by NMR spectroscopy

McDowell, C. A.; Naito, Akira; Sastry, D.L.; Takegoshi, K.

doi:10.1016/0022-2364(86)90079-x

Cited by 22 publications

(40 citation statements)

References 30 publications

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“…[9]. The 14 N nuclei in c-glycine have a quadrupolar coupling constant of C Q = 1.18 MHz, and an electric field gradient (efg) asymmetry parameter of g Q = 0.5 [13,22,35]. However, in other samples, 14 N nuclei can be subject to larger quadrupole interactions [14,23,24,36].…”

Section: Simulation Parametersmentioning

confidence: 99%

Broadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period

Trébosc

Lafon

et al. 2013

Journal of Magnetic Resonance

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N Broadband excitation DANTE MAS Paramagnetic samples a b s t r a c tWe analyze the direct excitation of wide one-dimensional spectra of nuclei with spin I = 1/2 or 1 in rotating solids submitted to pulse trains in the manner of Delays Alternating with Nutations for Tailored Excitation (DANTE), either with one short rotor-synchronized pulse of duration s p in each of K rotor periods For nuclei with I = 1 (e.g., for 14 N), the response to basic D K 1 pulse train is moreover affected by inhomogeneous decay due to 2nd-order quadrupole interactions, since these are not of rank 2 and therefore cannot be eliminated by spinning about the magic angle. For large quadrupole interactions, the signal decay produced by second-order quadrupole interaction can be minimized by (i) reducing the length of D K N pulse trains using N > 1, (ii) fast spinning, (iii) large rf-field, and (iv) using high magnetic fields to reduce the 2nd-order quadrupole interaction.

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Section: Simulation Parametersmentioning

confidence: 99%

Broadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period

Trébosc

Lafon

et al. 2013

Journal of Magnetic Resonance

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“…McDowell and co-workers applied 1 H-14 N cross-polarization with 1 H decoupling to study a series of single-crystal amino acids (L-serine-monohydrate [19], L-aspargine monohydrate [20] and L-histidine hydrochloride monohydrate [21]) using a probe specially designed to reduce acoustic ringing and featuring an accurate goniometer for adjustment of the crystal orientation [22]. In addition to a determination of the 14 N EFG parameters, they also studied the effects of 14 N- 13 C dipolar couplings on the 13 C spectra, an analysis of which allows a determination of the sign of the 14 N C Q as mentioned in Section 2 (such phenomena are discussed in more detail elsewhere [1] [26], and this work is discussed in Section 4.2.…”

Section: Single-crystal Samplesmentioning

confidence: 99%

Direct detection of nitrogen-14 in solid-state NMR spectroscopy

O’Dell¹

2011

Progress in Nuclear Magnetic Resonance Spectroscopy

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“…However, significant deviations from linearity have been reported for some compounds, and these have been assigned to external influences on the N ⑀ nitrogen (45). The role of such external influence can be illustrated using the nqi data for the N ␦ and N ⑀ atoms in L-histidine monochloride monohydrate where the crystallographic structure is also available (41) o (50). The analysis of the nqi tensors using the TownesDailey model revealed that shorter hydrogen bonding at the N ⑀ nitrogen site caused a greater electron population in the N-H orbital than that in the p orbital, whereas for the N ␦ those populations are essentially equal (49).…”

Section: The Characteristics Of H-bonded Imidazole Nitrogen-the Nqi Cmentioning

confidence: 99%

Hydrogen Bonds between Nitrogen Donors and the Semiquinone in the Qi-site of the bc1 Complex

Dikanov

Holland

Endeward

et al. 2007

Journal of Biological Chemistry

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The ubisemiquinone stabilized at the Q i -site of the bc 1 complex of Rhodobacter sphaeroides forms a hydrogen bond with a nitrogen from the local protein environment, tentatively identified as ring N from His-217. The interactions of 14 N and 15 N have been studied by X-band (ϳ9.7 GHz) and S-band (3.4 GHz) pulsed EPR spectroscopy. The application of S-band spectroscopy has allowed us to determine the complete nuclear quadrupole tensor of the 14 N involved in H-bond formation and to assign it unambiguously to the N ⑀ of His-217. This tensor has distinct characteristics in comparison with H-bonds between semiquinones and N ␦ in other quinone-processing sites. The experiments with 15 N showed that the N ⑀ of His-217 was the only nitrogen carrying any considerable unpaired spin density in the ubiquinone environment, and allowed calculation of the isotropic and anisotropic couplings with the N ⑀ of His-217. From these data, we could estimate the unpaired spin density transferred onto 2s and 2p orbitals of nitrogen and the distance from the nitrogen to the carbonyl oxygen of 2.38 ؎ 0.13 Å . The hyperfine coupling of other protein nitrogens with semiquinone is <0.1 MHz. This did not exclude the nitrogen of the Asn-221 as a possible hydrogen bond donor to the methoxy oxygen of the semiquinone. A mechanistic role for this residue is supported by kinetic experiments with mutant strains N221T, N221H, N221I, N221S, N221P, and N221D, all of which showed some inhibition but retained partial turnover.The bc 1 complex (ubihydroquinone:cytochrome c oxidoreductase, or complex III of the mitochondrial respiratory chain) functions to oxidize ubihydroquinone (QH 2 , 4 quinol) in the membrane and reduce cytochrome c (or cytochrome c 2 in bacteria) in the aqueous phase, using the redox work to transport 2H ϩ per electron across the membrane (1-4). In the photosynthetic bacterium Rhodobacter sphaeroides, the bc 1 complex completes the photosynthetic chain containing the photochemical reaction center, which provides the substrates for the complex following photoactivation (5, 6). The Q-cycle mechanism is a well tested model to account for the function of the bc 1 complex (7-9), but several details are still controversial. The Q-cycle involves separate catalytic sites on opposite sides of the membrane for oxidation of QH 2 and reduction of ubiquinone (Q, quinone). The work function is provided by a bifurcation of electron transfer at the quinol-oxidizing site (the Q osite). The first electron is transferred to a high potential chain (the Rieske iron-sulfur protein, cytochrome c 1 , and cytochrome c), and the second to a low potential chain, consisting of heme b L and heme b H in cytochrome b, which delivers electrons to the quinone reduction site (Q i -site). Some of the work from the first electron transfer is stored in the strong reducing potential of an unstable semiquinone intermediate formed at the Q o -site. This provides the driving force for reduction of Q, or of ubisemiquinone (SQ), in the Q i -site, and for generation of the p...

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Determination of the 14N quadrupole coupling tensors in a single crystal of l-histidine hydrochloride monohydrate by NMR spectroscopy

Cited by 22 publications

References 30 publications

Broadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period

Broadband excitation in solid-state NMR using interleaved DANTE pulse trains with N pulses per rotor period

Direct detection of nitrogen-14 in solid-state NMR spectroscopy

Hydrogen Bonds between Nitrogen Donors and the Semiquinone in the Qi-site of the bc1 Complex

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