Structural characterization of the acetylated heteroxylan from the natural hybrid Paulownia elongata/Paulownia fortunei.
The heteroxylan from the hybrid Paulownia elongata/Paulownia fortunei is an O-acetyl-(4-O-methylglucurono)xylan with an acetylation degree (DS) of 0.59 and a molecular weight (M(w)) of 29 kDa. The heteroxylan backbone is composed by (1-->4)-linked beta-d-xylopyranosyl units (Xylp) partially ramified with terminal (1-->2)-linked 4-O-methyl-alpha-D-glucuronosyl (MeGlcpA) and a small proportion of alpha-D-glucuronosyl (GlcpA) residues in a molar ratio of Xylp:(MeGlcpA+GlcpA) of 20:1. Roughly half of the beta-D-xylopyranosyl units in the backbone are acetylated: 3-O-acetylated (22 mol %), 2-O-acetylated (23 mol %) or 2,3-di-O-acetylated (7 mol %). ESI-MS and MALDI-MS studies of partially hydrolyzed heteroxylan revealed a random distribution of O-Ac and MeGlcpA within the backbone. However, the frequency of substitution with O-Ac along the backbone is not uniform and the molecular regions that did not contain MeGlcpA substituents possessed an acetylation degree significantly lower than the average DS of the xylan.
Mass Spectrometry Center/Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Virgínia M F
VM
Gonçalves
Dmitry V
DV
Evtuguin
M Rosário M
MR
Domingues
D000107:Acetylation; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D010944:Plants / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014990:Xylans / Q000737:chemistry*; D014994:Xylose
D014990:Xylans; D014994:Xylose