The crystal structure of the complex salt imidazole imidazolium perchlorate

Quick, Andrew; Williams, David J.

doi:10.1139/v76-350

Cited by 20 publications

(20 citation statements)

References 3 publications

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“…----- Figure 1 hereabouts---------- Figure 2 hereabouts---------- Table 1 hereabouts-----Calculated geometrical parameters are reported in Table 2, together with the structural parameters obtained from neutron diffraction and X-ray diffraction studies [26,27]. On the imidazole ring, the valence angles between non-hydrogen atoms are in the range of 105 o -110 o , referring to a significant ring distortion.…”

Section: Molecular Structure Of Poly(nvim)mentioning

confidence: 99%

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

Talu

Demiroğlu

Yurdakul

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Section: Molecular Structure Of Poly(nvim)mentioning

confidence: 99%

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

Talu

Demiroğlu

Yurdakul

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…In ribonuclease, a strong hydrogen bond between two histidine residues has been described (41). Such interactions have been studied by using imidazole and imidazolium, which form cocrystals displaying a strong hydrogen bond (42), and modeling them computationally (43). In addition, this imidazoleimidazolium sample and other complexes (44) have been extensively studied by solid-state NMR (45,46).…”

mentioning

confidence: 99%

Histidines, heart of the hydrogen ion channel from influenza A virus: Toward an understanding of conductance and proton selectivity

Nishimura

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

240

450

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The heart of the H ؉ conductance mechanism in the homotetrameric M2 H ؉ channel from influenza A is a set of four histidine side chains. Here, we show that protonation of the third of these imidazoles coincides with acid activation of this transmembrane channel and that, at physiological pH, the channel is closed by two imidazole-imidazolium dimers, each sharing a low-barrier hydrogen bond. This unique construct succeeds in distributing a pair of charges over four rings and many atoms in a low dielectric environment to minimize charge repulsion. These dimers form with identical pK as of 8.2 ؎ 0.2, suggesting cooperative H ؉ binding and clearly illustrating high H ؉ affinity for this channel. The protonation behavior of the histidine side chains has been characterized by using solid-state NMR spectroscopy on the M2 transmembrane domain in fully hydrated lipid bilayers where the tetrameric backbone structure is known. Furthermore, electrophysiological measurements of multichannel and single-channel experiments confirm that these protein constructs are functional.M2 channel ͉ proton channel ͉ solid-state NMR ͉ low-barrier hydrogen bond ͉ histidine ionization constants A histidine tetrad in the pore of the tetrameric M2 protein has long been associated with key channel features of H ϩ selectivity, pH activation, gating, inhibition, and the specific conductance mechanism. M2 protein from influenza A virus conducts protons into the viral core after endocytosis, which leads to the uncoating and release of genetic material into the cytoplasm after fusion of the viral coat with the endosomal wall (1, 2). Much is known about this system from its tetrameric state (2-4), the backbone structure of the transmembrane (TM) domain (5), and numerous electrophysiological (6, 7), biophysical (8-10), and modeling (11) studies that have cast a fascinating tale for this important influenza drug target and the only proton channel of its kind to be characterized in such detail. However, the specific role of His-37 in the tetrameric protein has not been elucidated. Here, we have characterized the pK a s associated with this cluster of four histidine residues in the hydrophobic interstices of the membrane. These pK a values have led us to substantial mechanistic conclusions.There are many lines of evidence, reviewed by Kelly et al. (6), that support the conclusion that M2 is responsible for viral acidification. In vivo ion conductance recordings have shown pH sensitive conductance resulting in rapid acidification of the Xenopus oocytes (12, 13) and mammalian cells (13-15) containing M2 protein.Preparations of purified M2 protein have also been used to show proton conductance in synthetic lipid bilayers (16,17). Singlechannel conductance measurements with membranes containing M2 protein give clear evidence that it is H ϩ conductance, not counterion conductance, that is observed. Furthermore, the channel conductance is unchanged by addition of an excess of NaCl (18). Conductance measurements for the isolated TM domain of M2 protein have als...

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“…We note that the structure of an imidazole‚‚‚H + ‚‚‚imidazole complex obtained by treating imidazole with perchloric acid has been reported. 22 Solid-state NMR. The aliphatic part of the 13 C CP/MAS spectrum of 1 recorded at room temperature with MAS at 10 kHz (Figure 3 At slow (2.5 kHz) MAS the isotropic lines of C2, C4, and C5 carbons are flanked by spinning sidebands caused by the large chemical shift anisotropy (Figure 3b).…”

Section: Resultsmentioning

confidence: 99%

“…The purpose of our calculations was to answer two questions: (i) Is it possible to correlate the 13 C chemical shift difference between the C4 and C5 atoms (∆δC4C5) with the N‚‚‚H + distance? (ii) Are the different values of δ 22 and κ for the C2 carbon in complex 1 and imidazole casual or do they represent a general tendency? If there is a positive answer to these questions, a simple analysis of 13 C chemical shift parameters could provide insights into the strength of hydrogen bonding and localization of the proton in the N‚‚‚H + ‚‚‚N unit.…”

Section: Resultsmentioning

confidence: 99%

“…The complex has been used to model molecular interactions in the solid state related to changes in the 13 C NMR parameters of the Im‚‚‚H + ‚‚‚Im fragment. A comparison of 13 C CP/MAS NMR results for complex 1 and imidazole shows different isotropic chemical shifts for the C4 and C5 carbons, and the δ 22 and κ parameters for the C2 carbon for the two compounds. The results were rationalized by GIAO calculations to establish Table 4.…”

Section: Discussionmentioning

confidence: 96%

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Structural Studies of the Bisimidazole 5,5-Dimethyl-1,3,2-Dioxaphosphorinane-2-Thioxo-2-Hydroxy Complex

et al. 1998

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The molecular complex of imidazole (Im) with 5,5-dimethyl-1,3,2-dioxaphosphorinane-2-thioxo-2-hydroxy acid (DPTHA) involves strong (O-H‚‚‚H and N .. H + ‚‚‚N) and weak (C-H‚‚‚O and C-H‚‚‚S) hydrogen bonds and has an unusual molecular packing. The crystals are monoclinic, space group I2/m, with a ) 10.609 (5) (000) ) 672, and µ ) 2.760 mm -1 . A comparison of 13 C CP/MAS NMR data for imidazole and the Im‚‚‚H + ‚‚‚Im cation shows that the 13 C isotropic chemical shifts of the C4 and C5 carbons, and of the δ 22 and κ parameters for C2 carbons for each compound are different. GIAO calculations at the HF/6-311 + G(2d,p)//B3LYP/6-31G* level reveal correlations between the differences in the 13 C chemical shift between the C4 and C5 atoms, the values of δ 22 and κ for the C2 carbon, and the N‚‚‚H + distance. An analysis of 13 C chemical shift parameters provides information about the strength of the hydrogen bonds and the localization of the proton in the N‚‚‚H + ‚‚‚N linkage.

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The crystal structure of the complex salt imidazole imidazolium perchlorate

Cited by 20 publications

References 3 publications

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

FTIR, Raman and NMR spectroscopic and DFT theoretical studies on poly(N-vinylimidazole)

Histidines, heart of the hydrogen ion channel from influenza A virus: Toward an understanding of conductance and proton selectivity

Structural Studies of the Bisimidazole 5,5-Dimethyl-1,3,2-Dioxaphosphorinane-2-Thioxo-2-Hydroxy Complex

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