Fig. 2
Activity of TtAA10A on polysaccharides. a MALDI-TOF MS spectrum of products obtained after incubation of 4 mg/mL Avicel with 2 µM LPMO and 4 mM gallic acid, showing native and oxidised oligosaccharides. The main peaks correspond to: C1 or C4 keto adduct, monosodiated adduct (− 2 species); C4 keto plus C1 aldonic acid, monosodiated adduct (+ 14 species); C1 aldonic acid or C4 gemdiol, monosodiated adduct (+ 16 species); C4 gemdiol plus C1 aldonic acid, monosodiated adduct (+ 32 species) and disodium adduct (+ 54); C1 aldonic acid, disodium adduct (+ 38 species). An additional peak with mass 1083 m/z could not be reliably assigned to any known product of LPMO oxidation and was tentatively interpreted as a higher oxidation level at the C6 (+ 70 species, corresponding to C4 gemdiol plus C1 aldonic acid plus C6 aldonic acid, disodium adduct). Native and oxidised species are marked in black and red, respectively. Relative intensity represents 1.23 × 103. b Expanded mass spectra for DP6. Synergy experiment showing the release of cellobiose from microcrystalline cellulose (Avicel) by a commercial GH6 (c) and of cellopentaose by a commercial GH9 (d). The LMPO significantly boosts the activity of both glycoside hydrolases, and such effect is increased by addition of gallic acid