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<p>Following our recent study, the current work performed to explore and elucidate the impacts of the length/angle of hydrogen bonds (H-bonds) of N–H···O/C–H···O type and the percentage s-character of the <i>σ</i>*<sub>N–H</sub>/<i>σ</i>*<sub>C–H</sub> antibonds partner in the charge transfer (CT) interactions on the nuclear shielding, anisotropy, quadrupole coupling constant, and asymmetry parameters of the imide, amide, carboxamide, and annular nitrogens/methine, methylene, and methyl carbons in the interacting inhibitor–residue pairs in capuramycin, carbacaprazamycin, 3ʹ-hydroxymureidomycin A, and muraymycin D2 binding pockets of MraY<sub>AA</sub>–inhibitor complexes (labeled as the QM models I–IV). The cited parameters were calculated at the M06-2X/6-31G** level by including the solvent effects using the polarizable continuum model. In the cases of the imide, amide, carboxamide, and annular nitrogens, the results outlined that a reduction in the H-bond length and an increase in s-character of the N hybrid in the <i>σ</i>*<sub>N–H</sub> antibond are associated with a decrease in the <sup>15</sup>N nuclear shielding as well as in the <sup>14</sup>N quadrupole coupling constant but with an enhancement in the <sup>15</sup>N anisotropy and also in the <sup>14</sup>N asymmetry parameter. The similar trends were observed for the nuclear shielding–length, nuclear shielding–s-character, anisotropy–length, anisotropy–s-character correlations of the methine, methylene, and methyl carbons. In addition, when the angles of C–H···O H-bonds are close to 180°, the <sup>13</sup>C anisotropies increase, while the <sup>13</sup>C nuclear shieldings decrease. The information obtained here has an immense impact on predicting the behavior of the <sup>15</sup>N/<sup>13</sup>C chemical shifts with the H-bonding characteristics in the protein–ligand complexes.</p>

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Quantum Chemical Studies of the Impacts of Various Aspects of Hydrogen Bonds on the NMR and NQR Parameters of Nitrogen and Carbon Nuclei Within the MraYAA–Nucleoside Inhibitor Binding Pockets

  • 期刊论文

  • 发表日期：

    2025年10月20日

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  • Elahe K. Astani,
  • Hossein Iravani,
  • Farhad Zahedi,
  • Soroush Sardari

摘要

Following our recent study, the current work performed to explore and elucidate the impacts of the length/angle of hydrogen bonds (H-bonds) of N–H···O/C–H···O type and the percentage s-character of the σ*N–H/σ*C–H antibonds partner in the charge transfer (CT) interactions on the nuclear shielding, anisotropy, quadrupole coupling constant, and asymmetry parameters of the imide, amide, carboxamide, and annular nitrogens/methine, methylene, and methyl carbons in the interacting inhibitor–residue pairs in capuramycin, carbacaprazamycin, 3ʹ-hydroxymureidomycin A, and muraymycin D2 binding pockets of MraYAA–inhibitor complexes (labeled as the QM models I–IV). The cited parameters were calculated at the M06-2X/6-31G** level by including the solvent effects using the polarizable continuum model. In the cases of the imide, amide, carboxamide, and annular nitrogens, the results outlined that a reduction in the H-bond length and an increase in s-character of the N hybrid in the σ*N–H antibond are associated with a decrease in the 15N nuclear shielding as well as in the 14N quadrupole coupling constant but with an enhancement in the 15N anisotropy and also in the 14N asymmetry parameter. The similar trends were observed for the nuclear shielding–length, nuclear shielding–s-character, anisotropy–length, anisotropy–s-character correlations of the methine, methylene, and methyl carbons. In addition, when the angles of C–H···O H-bonds are close to 180°, the 13C anisotropies increase, while the 13C nuclear shieldings decrease. The information obtained here has an immense impact on predicting the behavior of the 15N/13C chemical shifts with the H-bonding characteristics in the protein–ligand complexes.