Project description:The plant hemicellulose xyloglucan (XyG) is secreted from the roots of numerous plant species, including cereals, and contributes towards soil aggregate formation in terrestrial systems. Whether XyG represents a key nutrient for plant-associated bacteria is unclear. The phylum Bacteroidota are abundant in the plant microbiome and provide several beneficial functions for their host. However, the metabolic and genomic traits underpinning their success remain poorly understood. Here, we employed whole-cell proteomics to determine the molecular mechanisms responsible for xyloglucan utilisation in two model Flavobacterium species, Flavobacterium johnsoniae DSM2064 and Flavobacterium sp. OSR005. We identified the occurrence of a distinct and conserved gene cluster, referred to as the Xyloglucan Utilisation Loci (XyGUL). Flavobacterium XyGUL is a hybrid of the molecular machinery found in gut Bacteroides spp., Cellvibrio japonicus, and the plant pathogen Xanthomonas. Combining protein biochemistry, computational modelling and phylogenetics, we identified a mutation in the enzyme required for initiating hydrolysis of the XyG polysaccharide, an outer membrane endoxyloglucanase glycoside hydrolase family 5 subfamily 4 (GH5_4), which enhances activity towards XyG.
Project description:The soil bacterium Flavobacterium johnsoniae was grown on agar plates with or without pectin,bacteria were harvested, lysed, and subjected to LC-MS/MS analysis
Project description:Clinical Flavobacterium columnare ATCC 49512 was grown on Flavobacterium columnare growth medium (FCGM). Bacteria from four colonies at mid-exponential phase were harvested, total proteins were isolated, and identified using 2-DE MALDI TOF/TOF MS and 2-D LC ESI MS/MS analyses. The MS/MS spectra for all peptides were analyzed using sequest algorithm