Characterization of a novel multifunctional glycoside hydrolase family in the metagenome-assembled genomes of horse gut.

The researchers analyzed the genomes of microbes found in the horse gut and uncovered a hitherto unknown protein that has broad potential applications due to its ability to break down various carbohydrates.

Methodology

• In this study, the researchers analyzed over 4100 metagenome-assembled genomes (MAGs) derived from the gut microbiota of horses.
• They focused on the MAG117.bin13 genome, which belongs to Bacteroides fragilis, a bacterium that showed potential high carbohydrate degradation ability inferred from its high number of polysaccharide utilisation loci (PUL) sites.
• Through bioinformatics analysis, unidentified proteins, referred to as hypothetical proteins, were found in the PULs region of the studied genome. These proteins are crucial in the search for new carbohydrate-active enzymes (CAZymes).
• A specific hypothetical protein, labeled as BfLac2275, became of particular interest due to its potential activity in breaking down carbohydrates and its low similarity to other known CAZymes.

Findings

• The researchers were able to purify the BfLac2275 protein and conducted series of experiments to evaluate its enzymatic functions, particularly its ability to hydrolyze polysaccharides.
• Testing on different polysaccharide substrates revealed that BfLac2275 has efficient degradation ability for α-lactose, maltose, raffinose, and hyaluronic acid, with activity measurements given in units per milligram (U/mg).
• Optimal enzyme activity was observed at a pH of 5.0 and a temperature of 30°C, suggesting that BfLac2275 performs at its best under these conditions.
• Based on these results, the researchers classified BfLac2275 as a new and multifunctional glycoside hydrolase, a subcategory of CAZymes.

Potential Applications & Future Directions

• The capabilities of BfLac2275 indicate it may have wide-ranging applications in various fields such as the decomposition of plant polysaccharides, food industry, animal feed additives, and enzyme preparations.
• This study serves as both a guide to finding new CAZymes in gut microbiota and a reference for conducting further research into the purpose of unidentified genes in other assembled genomes.