A conformational study of alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->O)-L-Ser by NMR 1H,1H T-ROESY experiments and molecular-dynamics simulations.
The conformational preference of alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->O)-L-Ser has been investigated by one-dimensional (1)H,(1)H T-ROESY experiments and molecular-dynamics simulations with CHARMM22 type of force fields and water as explicit solvent. Proton-proton distances were obtained from the simulations and subsequently experimentally determined distances could be derived. Measurements were performed on the title compound as well as on selectively deuterium-substituted analogues synthesized as part of this study to alleviate possible NMR spectroscopic difficulties. A very good agreement was present between the separate NMR experiments. In the subsequent analysis a key nuclear Overhauser effect between the anomeric protons in the two sugar residues was used to assess the conformational dynamics revealed by the molecular simulations. The combined results support a model in which two states are significantly populated as a result of flexibility around the bond defined by the glycosidic torsion angle psi.
Lycknert
Kristina
K
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
Helander
Anne
A
Oscarson
Stefan
S
Kenne
Lennart
L
Widmalm
Göran
G
D002236:Carbohydrate Conformation; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D008362:Mannosides / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry / Q000378:metabolism; D011522:Protons; D012694:Serine / Q000031:analogs & derivatives* / Q000737:chemistry*
D008362:Mannosides; D011506:Proteins; D011522:Protons; C077466:O-(2-O-mannopyranosyl-mannopyranosyl)serine; D012694:Serine