N.m.r. and molecular-modelling studies of the solution conformation of heparin.
The solution conformations of heparin and de-N-sulphated, re-N-acetylated heparin have been determined by a combination of n.m.r. spectroscopic and molecular-modelling techniques. The 1H- and 13C-n.m.r. spectra of these polysaccharides have been assigned. Observed 1H-1H nuclear Overhauser enhancements (n.O.e.s) have been simulated using the program NOEMOL [Forster, Jones and Mulloy (1989) J. Mol. Graph. 7, 196-201] for molecular models derived from conformational-energy calculations; correlation times for the simulations were chosen to fit experimentally determined 13C spin-lattice relaxation times. In order to achieve good agreement between calculated and observed 1H-1H n.O.e.s it was necessary to assume that the reorientational motion of the polysaccharide molecules was not isotropic, but was that of a symmetric top. The resulting model of heparin in solution is similar to that determined in the fibrous state by X-ray-diffraction techniques [Nieduszynski, Gardner and Atkins (1977) Am. Chem. Soc. Symp. Ser. 48, 73-80].
Mulloy
B
B
National Institute for Biological Standards and Control, South Mimms, Potters Bar, Herts, U.K.
Forster
M J
MJ
Jones
C
C
Davies
D B
DB
D002247:Carbon Isotopes; D004187:Disaccharides / Q000737:chemistry; D006493:Heparin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008970:Molecular Weight; D011487:Protein Conformation; D012996:Solutions; D014316:Tritium
D002247:Carbon Isotopes; D004187:Disaccharides; D012996:Solutions; D014316:Tritium; D006493:Heparin