Karplus equation for NMR coupling constants

E467020

The Karplus equation for NMR coupling constants is an empirical relationship that links three-bond scalar coupling values between nuclei to the dihedral angle between them, enabling the determination of molecular conformations from NMR data.

All labels observed (4)

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Statements (49)

Predicate Object
instanceOf NMR parameter correlation ⓘ
conformational analysis tool ⓘ
empirical relationship ⓘ
appliesTo H–C–C–H dihedral angles ⓘ
three-bond couplings across a single bond ⓘ
vicinal proton–proton couplings ⓘ
assumes coupling constant is periodic in dihedral angle ⓘ
maximum coupling near 180 degrees ⓘ
minimum coupling near 90 degrees ⓘ
calibratedBy experimental NMR data ⓘ
quantum chemical calculations ⓘ
category NMR structural restraints ⓘ
empirical structure–property relationships ⓘ
dependsOn dihedral angle θ between coupled nuclei ⓘ
empirical parameters A, B, and C ⓘ
describes 3J spin–spin coupling constants ⓘ
three-bond scalar coupling constants ⓘ
field nuclear magnetic resonance spectroscopy ⓘ
physical chemistry ⓘ
structural chemistry ⓘ
hasVariant Karplus equation for 3J(HN,Hα) in proteins ⓘ
Karplus-like equations for heteronuclear couplings ⓘ
generalized Karplus equation ⓘ
historicalContext introduced in the 1950s ⓘ
involves cosine-squared angular dependence ⓘ
periodicity of 360 degrees in θ ⓘ
limitation accuracy decreases for highly substituted systems ⓘ
does not explicitly include dynamic averaging ⓘ
parameters are system-dependent ⓘ
mathematicalForm J = A cos²(θ) + B cos(θ) + C ⓘ
namedAfter Martin Karplus ⓘ
parameter A ⓘ
B ⓘ
C ⓘ
predicts magnitude of 3J coupling constants ⓘ
relatedTo J-coupling based structure refinement ⓘ
Ramachandran plot analysis in proteins ⓘ
relates 3J coupling constants to dihedral angles ⓘ
NMR coupling constants to molecular conformation ⓘ
sensitivityTo bond geometry ⓘ
electronegativity of substituents ⓘ
substituent effects ⓘ
usedFor conformational analysis of organic molecules ⓘ
determining dihedral angles from NMR data ⓘ
peptide and protein structure determination ⓘ
protein backbone torsion angle estimation ⓘ
validating molecular dynamics simulations ⓘ
usedIn solid-state NMR adaptations ⓘ
solution-state NMR spectroscopy ⓘ

How these facts were elicited

Referenced by (4)

Full triples — surface form annotated when it differs from this entity's canonical label.

Martin Karplus → hasWork → Karplus equation for NMR coupling constants ⓘ
Karplus equation → hasExtension → stereospecific Karplus relationships ⓘ
linked to: Karplus equation for NMR coupling constants
Karplus equation for NMR coupling constants → hasVariant → generalized Karplus equation ⓘ
linked to: Karplus equation for NMR coupling constants
Karplus equation for NMR coupling constants → hasVariant → Karplus equation for 3J(HN,Hα) in proteins ⓘ
linked to: Karplus equation for NMR coupling constants