Figure 1. Two-dimensional ¹H-¹H TOCSY NMR spectrum of acetylated xylan from wild-type Arabidopsis stems. Acetylated xylan was extracted with DMSO²⁸ and digested with β-endoxylanase M6 (Megazyme) to generate xylooligosaccharides,¹⁶ which were subsequently subject to structural analysis using NMR spectroscopy.²⁹ The spectra aligned at the top and the left of the figure are the 1D ¹H NMR spectra of Arabidopsis xylan. The identities of the resonance peaks in the top spectrum are marked. The following abbreviations are used: GlcA/MeGlcA-2Gal, GlcA/MeGlcA substituted at O-2 with galactose; Xyl-2,3Ac, 2,3-di-O-acetylated xylosyl residues; Xyl-3Ac-2GlcA, 3-O-acetylated xylosyl residues substituted with O-2 with GlcA/MeGlcA; Xyl-3Ac, 3-O-acetylated xylosyl residues.