Fig. 3: The esterase genes enriched (EGE) PUL of B. intestinalis encodes esterases with different specificities.

a The genomic context of the EGE PUL is color coded to show the predicted functions of the encoded polypeptides. b A schematic representation of the predicted domain architecture of the putative esterases and putative glycoside hydrolases in the EGE PUL. The N-terminally appended dark boxes indicate the predicted signal peptide is Type I (SPI) and therefore a likely periplasmic localization, while the open box indicates predicted signal peptide Type II (SPII) and therefore a predicted outer membrane or extracellular localization. c A 12% SDS-PAGE showing the purified (recombinant) putative esterases and glycoside hydrolases. d Substrate specificities of the putative esterases in the cluster on feruloylated monosaccharide (FA), feruloylated disaccharides (FAX, FA₂, FG₂), and feruloylated trisaccharides (FAXX, FAXG, FA₃). e Acetyl-xylan esterase activity towards acetylated oat spelt xylan. The synergistic activities of the enzymes encoded by the EGE PUL were assessed by incubating the enzymes and their different combinations with: (f) de-starched wheat bran and (g) insoluble wheat arabinoxylan. The released reducing ends were determined by the para-hydroxybenzoic acid hydrazide assay and the released ferulic acid was determined by HPLC-DAD. GH: glycoside hydrolase, CE: carbohydrate esterase, HTCS: Hybrid Two-Component System, and Sus: starch utilization system. In c, on purification, each protein was resolved on SDS-PAGE to ensure that they migrated according to their predicted molecular mass, and finally a single SDS-PAGE was ran with all proteins migrating to their individually detected positions relative to the protein molecular mass markers. In d–g, the bars are means ± standard deviations of three independent reactions (n = 3). The source data underlying (d–g) are provided in the Source Data file.