The three-dimensional structure of the mega-oligosaccharide rhamnogalacturonan II monomer: a combined molecular modeling and NMR investigation.
In this study, we describe the first optimized molecular models of the mega-oligosaccharide rhamnogalaturonan II, that is found in the primary cell walls of all higher plants. The 750 MHz 1H NMR data previously reported and new heteronuclear correlation spectra (sensitivity-enhanced HSQC and HSQC-TOCSY) were first reassigned in light of the modifications in the primary structure. In turn, the experimental NMR data revealed the presence of an additional sugar, alpha-Araf (E-chain), and also the disaccharidic repeating unit of RG-I, another component of the pectic matrix. Due to a fuller picture of the primary structure of RG-II, a much more complete assignment of the NOE data has been achieved. A systematic computational study based on these NOEs lead us to a realistic three-dimensional description of the RG-II, in excellent agreement with the molecular dimensions obtained from various experimental methods.
Rodríguez-Carvajal
Miguel A
MA
Centre de Recherches sur les Macromolécules Végétales, CNRS (associated with University Joseph Fourier), BP 53, 38041 Cedex 9, Grenoble, France.
Hervé du Penhoat
Catherine
C
Mazeau
Karim
K
Doco
Thierry
T
Pérez
Serge
S
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D009844:Oligosaccharides / Q000737:chemistry; D010368:Pectins / Q000737:chemistry* / Q000302:isolation & purification
D009844:Oligosaccharides; C042492:rhamnogalacturonan II; D010368:Pectins