Fig. 5

Characterisation of purified recombinant bacterial CAZymes encoded by the endosymbionts. A Schematic diagram showing the architecture of LpsGH5_8, LpsGH11, LpsGH134a, LpsGH134b and LpsAA10A, showing the N-terminal signal peptide for secretion and the main protein domains. B Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) performed on different substrates (listed on top of the figure) for the bacterial proteins LpsGH5_8 (with and without its CBM), LpsGH134a, LpsGH134b and LpsGH11 with their CBMs. LpsGH11 was tested only on grass xylan (miscanthus stem AIR) and using different protein amounts (detailed in the picture), while the other enzymes were tested on a wider range of substrates using 1 μg of protein. LBG = locust bean gum. M1 to M6 are mannan standards containing from one to six mannosyl residues; X1 to X6 are xylan standards. The negative controls are those with no substrate (right panel) or no protein (first lane of each panel). C MALDI-TOF MS spectrum of products obtained after incubation of LpsAA10A with PASC and gallic acid as electron donor. The main peaks correspond to mono- or di-sodiated adducts of C1-aldonic acids, imparting + 16 or + 38 m/z respectively, relative to the mono-sodiated unoxidised form. Smaller peaks for the mono-sodiated lactone (− 2) were also identified. All oxidised species are marked in red. The 100% relative intensity represents 1.0 × 10⁴ arbitrary units. Negative control reactions carried out with substrate only, substrate plus gallic acid and substrate plus LpsAA10A did not generate any oxidised products (see Additional file 13: Fig. S8). Inset shows the expanded mass spectra for DP7 (degree of polymerisation 7) products