FIG 6.

MALDI-TOF MS analysis of the reaction products generated by GtLPMO9A-2 (A) and NcLPMO9C (B) during the dynamic viscosity experiments with tamarind xyloglucan (XG) in the presence of reducing agent (DTT). The samples analyzed were the endpoint samples (16 h). The reaction conditions are specified in Materials and Methods and were similar to the conditions used for generating Fig. 5. GtLPMO9A-2 generated a wide range of oligosaccharides with all possible combination of hexose (Hex) and pentose (Pen) units, whereas NcLPMO9C generated clusters of oligosaccharides with the number of pentose residues being a multiple of three. In both spectra, oxidized species (−2, compared with the weight of native species) are marked with #; species with masses indicating arabinosylation are labeled green (see the text). Note that most labeled peaks in fact are a cluster of signals; see Fig. S10 in the supplemental material and text. All labeled species are Na⁺ adducts. No species were detected below m/z 1,000.