Figure 4.

Transfer of multiple xylosyl residues onto the Xyl₄-AA acceptor by microsomes with coexpression of PtrGT43B and PtrGT43C. Microsomes from transgenic BY2 cell lines transfected with the empty vector (control), PtrGT43B alone, PtrGT43C alone, or PtrGT43B and PtrGT43C together (PtrGT43B/C-2, -4 and -9) were incubated with UDP-Xyl and the fluorescent Xyl₄-AA acceptor, and the reaction products were analyzed by reverse-phase HPLC coupled with fluorescent detection. Note that the XylT activity in transgenic cell lines coexpressing PtrGT43B/C is able to successively elongate Xyl₄ to up to Xyl₁₁. The XylT activity of poplar stem microsomes is shown for comparison and a chromatogram of standard Xyl_1–6-AA is shown at the top left for reference.