Effect of steric compression on proton-proton, spin-spin coupling constants. Further evidence and mechanistic considerations

1970 ◽  
Vol 92 (15) ◽  
pp. 4646-4652 ◽  
Author(s):  
Marcus Ashley. Cooper ◽  
Stanley L. Manatt
Keyword(s):  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Proton ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

scholarly journals Glycosaminoglycan Monosaccharide Blocks Analysis by Quantum Mechanics, Molecular Dynamics, and Nuclear Magnetic Resonance

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Sergey A. Samsonov ◽  
Stephan Theisgen ◽  
Thomas Riemer ◽  
Daniel Huster ◽  
M. Teresa Pisabarro
Keyword(s):  
Molecular Dynamics ◽  
Dihedral Angle ◽  
Chemical Shifts ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Proton ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
The Impact

Glycosaminoglycans (GAGs) play an important role in many biological processes in the extracellular matrix. In a theoretical approach, structures of monosaccharide building blocks of natural GAGs and their sulfated derivatives were optimized by a B3LYP6311ppdd//B3LYP/6-31+G(d) method. The dependence of the observed conformational properties on the applied methodology is described. NMR chemical shifts and proton-proton spin-spin coupling constants were calculated using the GIAO approach and analyzed in terms of the method's accuracy and sensitivity towards the influence of sulfation, O1-methylation, conformations of sugar ring, andωdihedral angle. The net sulfation of the monosaccharides was found to be correlated with the1H chemical shifts in the methyl group of the N-acetylated saccharides both theoretically and experimentally. Theωdihedral angle conformation populations of free monosaccharides and monosaccharide blocks within polymeric GAG molecules were calculated by a molecular dynamics approach using the GLYCAM06 force field and compared with the available NMR and quantum mechanical data. Qualitative trends for the impact of sulfation and ring conformation on the chemical shifts and proton-proton spin-spin coupling constants were obtained and discussed in terms of the potential and limitations of the computational methodology used to be complementary to NMR experiments and to assist in experimental data assignment.

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