Figure 1.

General structure of XXXG-type xyloglucans and structures of α-glycosyl fluoride substrates for xyloglucan glycosynthases. (a) Variable substitution of the Xyl₃Glc₄ core repeat in xyloglucans. The standard xyloglucan structural abbreviations(55) are given below the corresponding motifs, assuming full branch substitution. For example, the galactoxyloglucan from tamarind seeds is predominantly comprised of XXXG, XXLG, and XLLG units, with minor amounts of XLXG units.(56) In contrast, the fucogalactoxyloglucan from Arabidopsis thaliana primary cell walls contains primarily XXXG, XXFG, and XLFG units, with minor amounts of other structures.(48) (b) α-Glycosyl fluoride substrates for xyloglucan glycosynthases.