ISSN:
1573-5001
Keywords:
3D NMR
;
Long-range J coupling
;
Carbon-carbon J coupling
;
χ 2 Torsion angle
;
Stereospecific assignment
;
Protein dynamics
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary A new 1H-detected 3D NMR experiment is described that permits quantitative measurement of two- and three-bond 13C−1H couplings in proteins with selectively 13C-enriched methyl sites. The method is demonstrated for staphylococcal nuclease selectively [5,5 13C]-labeled in all 11 leucine positions and ligated with thymidine 3′,5′-biphosphate and Ca2+. Two- and three-bond 13C methyl-proton couplings are reported and, together with the measured three-bond JCαCδ in uniformly 13C-enriched staphylococcal nuclease, the χ 2- and the stereospecific assignments of the Cδ methyl group with respect to the prochiral β-protons were determined. The same residues that were previously found to have high degrees of internal mobility on the basis of 13C relaxation times have measured coupling constants that are indicative of motional averaging.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00212516
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