Endoxylanase inhibition assay of XylB mutants with altered inhibition characteristics. Endoxylanase activities in the absence (gray bars) and presence (white bars) of XIP-I are shown. Clones 5, 7, and 9 represent the XylB-38TPSA41-62NH63-141N-T149, XylB-38GGGD41-62NH63-141N-T149, and XylB-38GGGD41-62NF63-141N-T149 mutants, respectively. Means and standard deviations of triplicate experiments are shown.