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- Title
Trans-Hydrogen-Bond Scalar Couplings as a Source of Structural Constraints in NMR of Proteins: DFT Analysis.
- Authors
Heinz, Tim; Moreira, Osvaldo; Pervushin, Konstantin
- Abstract
The conformational dependences of 15N,15N and 1H,15N trans-H-bond spin-spin scalar couplings, h2 J(N,N) and h1 J(N,H), have been investigated by sum-over-states density-functional-perturbation theory. The distance and angular dependence of the h2 J(N,N) and h1 J(N,H) coupling constants in the H-bonded arrangement between acetylethylamine and imidazole molecules were examined for a wide range of mutual orientations. These molecules were used to model a structurally important H-bond between the amide backbone of Arg7 and the remote imidazole side chain of His106 in the 44 kDa trimeric enzyme chorismate mutase from Bacillus subtilis. The magnitude of h1 J(N,H) is relatively insensitive to the sampled rotations around three orthogonal axes centered on the tertiary N-atom of the imidazole, whereas values of h2 J(N,N) demonstrated a strong dependence on the value of the cone angle θ aligned with the amide group involved in the H-bond. Simple functional approximations have been generated, enabling back calculations of the N⋅⋅⋅N distance and angle θ of the H-bond, provided that the experimental values of both h2 J(N,N) and h1 J(N,H) coupling constants are available.
- Publication
Helvetica Chimica Acta, 2002, Vol 85, Issue 11, p3984
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/1522-2675(200211)85:11<3984::AID-HLCA3984>3.0.CO;2-4