Resolving overlap in two-dimensional NMR spectra: nuclear Overhauser effects in a polysaccharide

2005 ◽  
Vol 43 (10) ◽  
pp. 791-794 ◽  
Author(s):  
Eriks Kupče ◽  
Toshiaki Nishida ◽  
Göran Widmalm ◽  
Ray Freeman
Keyword(s):  
Nmr Spectra ◽  
Two Dimensional ◽  
Nuclear Overhauser ◽  
Nuclear Overhauser Effects

Nuclear Overhauser effects and the assignment of the proton NMR spectra of proteins

FEBS Letters ◽  
1984 ◽  
Vol 176 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Christopher M. Dobson ◽  
Martin A. Howarth ◽  
Christina Redfield
Keyword(s):  
Nmr Spectra ◽  
Proton Nmr ◽  
Nuclear Overhauser ◽  
Nuclear Overhauser Effects

scholarly journals NMR solution conformation of heparin-derived tetrasaccharide

1996 ◽  
Vol 318 (1) ◽  
pp. 93-102 ◽  
Author(s):  
Dmitri MIKHAILOV ◽  
Kevin H. MAYO ◽  
Ioncho R. VLAHOV ◽  
Toshihiko TOIDA ◽  
Azra PERVIN ◽  
...  
Keyword(s):  
Chair Conformation ◽  
Coupling Constants ◽  
Solution Conformation ◽  
1H And 13C Nmr ◽  
Small Deviations ◽  
J Coupling Constants ◽  
Nuclear Overhauser ◽  
Nuclear Overhauser Effects ◽  
Dynamics Simulations ◽  
Ring Conformations

The solution conformation of the homogeneous, heparin-derived tetrasaccharide ΔUA2S(1 → 4)-α-d-GlcNpS6S(1 → 4)-α-l-IdoAp2S(1 → 4)-α-d-GlcNpS6S (residues A, B, C and D respectively, where IdoA is iduronic acid) has been investigated by using 1H- and 13C-NMR. Ring conformations have been defined by J-coupling constants and inter-proton nuclear Overhauser effects (NOEs), and the orientation of one ring with respect to the other has been defined by inter-ring NOEs. NOE-based conformational modelling has been done by using the iterative relaxation matrix approach (IRMA), restrained molecular dynamics simulations and energy minimization to refine structures and to distinguish between minor structural differences and equilibria between various ring forms. Both glucosamine residues B and D are in the 4C1 chair conformation. The 6-O-sulphate group is oriented in the gauche–trans configuration in the D ring, whereas in the B ring the gauche–gauche rotomer predominates. Uronate (A) and iduronate (C) residues are mostly represented by 1H2 and 2S0 twisted boat forms, respectively, with small deviations in expected coupling constants and NOEs suggesting minor contributions from other A and C ring conformations.

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