Date: Fri, 21 Jun 2002 07:49:40 -0700
From: "David A. Case"
Subject: Re: j3 coupling

On Fri, Jun 21, 2002, Yuguang Mu wrote:

> Do you know some discusses about the degree of accuracy of the Karplus
> relation of J3 coupling for H-N-Ca-Ha ?
> How much can we rely on it ?
>

Very good curves are known for proteins. See, e.g.

%A R. Brüschweiler
%A D.A. Case
%T Adding harmonic motion to the Karplus relation for spin-spin couplings
%J J. Am. Chem. Soc.
%V 116
%P 11199-11200
%D 1994

%A D.A. Case
%A C. Scheurer
%A R. Brüschweiler
%T Static and Dynamic Effects on Vicinal Scalar J Couplings in Proteins
and Peptides: A MD/DFT Analysis
%J J. Am. Chem. Soc.
%V 122
%P 10390-10397
%D 2000

%A A.C. Wang
%A A. Bax
%T Determination of the backbone dihedral angles `phi` in human ubiquitin
%from reparaetrized empirical Karplus equations
%J J. Am. Chem. Soc.
%V 118
%P 2483-2494
%D 1996

%A J.M. Schmidt
%A M. Blmel
%A F. Löhr
%A H. Rüterjans
%T Self-consistent \*{3\*}J coupling analysis for the joint calibration of
Karplus coefficients and evaluation of torsion angles
%J J. Biomol. NMR
%V 14
%P 1-12
%D 1999

..hope this helps....dac