Analysis of the NMR spin-spin coupling mechanism across a H-bond: nature of the H-bond in proteins

Tell Tuttle, Jürgen Gräfenstein, Anan Wu, Elfi Kraka, Dieter Cremer

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The NMR spin-spin coupling constants (SSCCs) across the H-bond in proteins are sensitive to the electronic structure of the H-bonded system, i.e., the N-H···O=C group in proteins. The spin-spin coupling mechanism across the H-bond involves a strong electric field effect, steric exchange interactions, and some weak covalent effects (transfer of electronic charge). The electric field effect is reflected by one-orbital contributions to the SSCC and can be tested with the help of probe charges. A negative charge opposite to the N-H bond leads to increased polarization of the N-H bond, a larger contact density at the N nucleus, and a stronger FC coupling mechanism for those SSCCs involving the N nucleus. Similarly, a positive charge opposite to the O=C bond, distorts the O density into the direction of the external charge and in this way decreases the spin density at the O nucleus. All SSCCs across the H-bond depend primarily on the electric field effect and two-orbital steric exchange interactions. The lone pair contributions to the Fermi contact ferm of 2h J(ON) (and to a lesser extent 3h J(CN)) provide a direct measure on possible covalent contributions in the form of charge-transfer interactions. According to calculated charge-transfer values and lone-pair contributions to SSCC 2h J(ON), the covalent contribution to the H-bond is rather small (less than 15% at 1.9 Å for a bending angle β(COH) of 120°). The zeroth-order density and the spin-spin coupling mechanism, which depends largely on the first-order spin density, both describe the H-bond as being electrostatic rather than covalent. The electric field effect largely determines the geometrical dependence of the SSCCs of a hydrogen-bonded system.

LanguageEnglish
Pages1115-1129
Number of pages15
JournalJournal of Physical Chemistry B
Volume108
Issue number3
Early online date24 Dec 2003
DOIs
Publication statusPublished - 22 Jan 2004

Fingerprint

Electric field effects
spin-spin coupling
Nuclear magnetic resonance
proteins
Proteins
nuclear magnetic resonance
Exchange interactions
Charge transfer
electric fields
nuclei
Electronic structure
Hydrogen
Electrostatics
charge transfer
Polarization
orbitals
interactions
electric contacts
electrostatics
electronic structure

Keywords

  • spin−spin coupling constants
  • SSCCs
  • H-bond
  • proteins

Cite this

Tuttle, Tell ; Gräfenstein, Jürgen ; Wu, Anan ; Kraka, Elfi ; Cremer, Dieter. / Analysis of the NMR spin-spin coupling mechanism across a H-bond : nature of the H-bond in proteins. In: Journal of Physical Chemistry B . 2004 ; Vol. 108, No. 3. pp. 1115-1129.
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abstract = "The NMR spin-spin coupling constants (SSCCs) across the H-bond in proteins are sensitive to the electronic structure of the H-bonded system, i.e., the N-H···O=C group in proteins. The spin-spin coupling mechanism across the H-bond involves a strong electric field effect, steric exchange interactions, and some weak covalent effects (transfer of electronic charge). The electric field effect is reflected by one-orbital contributions to the SSCC and can be tested with the help of probe charges. A negative charge opposite to the N-H bond leads to increased polarization of the N-H bond, a larger contact density at the N nucleus, and a stronger FC coupling mechanism for those SSCCs involving the N nucleus. Similarly, a positive charge opposite to the O=C bond, distorts the O density into the direction of the external charge and in this way decreases the spin density at the O nucleus. All SSCCs across the H-bond depend primarily on the electric field effect and two-orbital steric exchange interactions. The lone pair contributions to the Fermi contact ferm of 2h J(ON) (and to a lesser extent 3h J(CN)) provide a direct measure on possible covalent contributions in the form of charge-transfer interactions. According to calculated charge-transfer values and lone-pair contributions to SSCC 2h J(ON), the covalent contribution to the H-bond is rather small (less than 15{\%} at 1.9 {\AA} for a bending angle β(COH) of 120°). The zeroth-order density and the spin-spin coupling mechanism, which depends largely on the first-order spin density, both describe the H-bond as being electrostatic rather than covalent. The electric field effect largely determines the geometrical dependence of the SSCCs of a hydrogen-bonded system.",
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Analysis of the NMR spin-spin coupling mechanism across a H-bond : nature of the H-bond in proteins. / Tuttle, Tell; Gräfenstein, Jürgen; Wu, Anan; Kraka, Elfi; Cremer, Dieter.

In: Journal of Physical Chemistry B , Vol. 108, No. 3, 22.01.2004, p. 1115-1129.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Analysis of the NMR spin-spin coupling mechanism across a H-bond

T2 - Journal of Physical Chemistry B

AU - Tuttle, Tell

AU - Gräfenstein, Jürgen

AU - Wu, Anan

AU - Kraka, Elfi

AU - Cremer, Dieter

PY - 2004/1/22

Y1 - 2004/1/22

N2 - The NMR spin-spin coupling constants (SSCCs) across the H-bond in proteins are sensitive to the electronic structure of the H-bonded system, i.e., the N-H···O=C group in proteins. The spin-spin coupling mechanism across the H-bond involves a strong electric field effect, steric exchange interactions, and some weak covalent effects (transfer of electronic charge). The electric field effect is reflected by one-orbital contributions to the SSCC and can be tested with the help of probe charges. A negative charge opposite to the N-H bond leads to increased polarization of the N-H bond, a larger contact density at the N nucleus, and a stronger FC coupling mechanism for those SSCCs involving the N nucleus. Similarly, a positive charge opposite to the O=C bond, distorts the O density into the direction of the external charge and in this way decreases the spin density at the O nucleus. All SSCCs across the H-bond depend primarily on the electric field effect and two-orbital steric exchange interactions. The lone pair contributions to the Fermi contact ferm of 2h J(ON) (and to a lesser extent 3h J(CN)) provide a direct measure on possible covalent contributions in the form of charge-transfer interactions. According to calculated charge-transfer values and lone-pair contributions to SSCC 2h J(ON), the covalent contribution to the H-bond is rather small (less than 15% at 1.9 Å for a bending angle β(COH) of 120°). The zeroth-order density and the spin-spin coupling mechanism, which depends largely on the first-order spin density, both describe the H-bond as being electrostatic rather than covalent. The electric field effect largely determines the geometrical dependence of the SSCCs of a hydrogen-bonded system.

AB - The NMR spin-spin coupling constants (SSCCs) across the H-bond in proteins are sensitive to the electronic structure of the H-bonded system, i.e., the N-H···O=C group in proteins. The spin-spin coupling mechanism across the H-bond involves a strong electric field effect, steric exchange interactions, and some weak covalent effects (transfer of electronic charge). The electric field effect is reflected by one-orbital contributions to the SSCC and can be tested with the help of probe charges. A negative charge opposite to the N-H bond leads to increased polarization of the N-H bond, a larger contact density at the N nucleus, and a stronger FC coupling mechanism for those SSCCs involving the N nucleus. Similarly, a positive charge opposite to the O=C bond, distorts the O density into the direction of the external charge and in this way decreases the spin density at the O nucleus. All SSCCs across the H-bond depend primarily on the electric field effect and two-orbital steric exchange interactions. The lone pair contributions to the Fermi contact ferm of 2h J(ON) (and to a lesser extent 3h J(CN)) provide a direct measure on possible covalent contributions in the form of charge-transfer interactions. According to calculated charge-transfer values and lone-pair contributions to SSCC 2h J(ON), the covalent contribution to the H-bond is rather small (less than 15% at 1.9 Å for a bending angle β(COH) of 120°). The zeroth-order density and the spin-spin coupling mechanism, which depends largely on the first-order spin density, both describe the H-bond as being electrostatic rather than covalent. The electric field effect largely determines the geometrical dependence of the SSCCs of a hydrogen-bonded system.

KW - spin−spin coupling constants

KW - SSCCs

KW - H-bond

KW - proteins

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