¹H NMR analysis of acetyl xylooligomers from PtrXOAT-complemented <i>esk1</i> plants.

<p>DMSO-extracted acetyl xylans were digested with xylanase and the acetylation patterns of released xylooligomers were analyzed using ¹H NMR spectroscopy. (A) ¹H NMR spectra of acetyl xylooligomers from the wild type, <i>esk1</i>, and PtrXOAT-complemented <i>esk1</i>. Acetyl xylooligomers from ESK1-complemented <i>esk1</i> were used for comparison. The spectra in the left panel show the resonances attributed to carbohydrate (3.0–5.5 ppm) and acetyl groups (2.0–2.25 ppm). The enlarged spectra in the right panel show the resonances corresponding to acetyl groups in Xyl-2,3Ac, Xyl-3Ac, Xyl-2Ac, and Xyl-3Ac-2GlcA. There was a slight shift in the position of the resonance signal for Xyl-3Ac-2GlcA in some samples. (B) Integration analysis of the degree of acetyl substitution in xylans from the wild type, <i>esk1</i>, and PtrXOAT-complemented <i>esk1</i> based on the resonance signals for the carbohydrate and the acetyl groups in (A). The relative amount of acetyl groups (% of WT) was determined by the ratio of acetyl groups in the xylans of PtrXOAT-complemented <i>esk1</i> over that of the wild type (taken as 100).