ISSN:
1573-5001
Keywords:
Coupling constant
;
Linewidth
;
TOCSY
;
NOESY
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract A simple linear relationship between the J $$_{_H N_H \alpha }$$ coupling constant and the linewidth (Δν1/2) of in-phase NMR peaks has been identified. This relationship permits the rapid and accurate determination of polypeptide J $$_{_H N_H \alpha }$$ coupling constants from a simple inspection of amide cross peaks in homonuclear 1H TOCSY or 1H NOESY spectra. By using the appropriate set of processing parameters we show that J $$_{_H N_H \alpha }$$ = 0.5(Δν1/2) − MW/5000 + 1.8 for TOCSY spectra and J $$_{_H N_H \alpha }$$ = 0.6(Δν1/2) − MW/5000 − 0.9 for NOESY spectra, where Δν1/2 is the half-height linewidth in Hz and MW is the molecular weight of the protein in Da. The simplicity of this relationship, combined with the ease with which Δν1/2 measurements can be made, means that J $$_{_H N_H \alpha }$$ coupling constants can now be rapidly determined (up to 100 measurements in less than 30 min) without the need for any complex curve-fitting algorithms. Tests on 11 different polypeptides involving more than 650 separate J $$_{_H N_H \alpha }$$ measurements have shown that this method yields coupling constants with an rmsd error (relative to X-ray data) of less than 0.9 Hz. Furthermore, the correlation coefficient between the predicted NMR coupling constants and those derived from high-resolution X-ray crystal structures is typically better than 0.89. These simple linear relationships have been found to be valid for peptides as small as 1 kDa to proteins as large as 20 kDa. Despite the method's simplicity, these results are comparable to the accuracy and precision of the best techniques published to date.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1018315729609
Permalink