Biochemical characterization of bifunctional enzymatic activity of a recombinant protein (Bp0469) from Blautia producta ATCC 27340 and its role in the utilization of arabinogalactan oligosaccharides

Human consumption of larch arabinogalactan has a significant effect on enhancing probiotic microflora in the gut, and it also promotes the production of short-chain fatty acids. Bacterial members of Lachnospiraceae family are important and play significant roles in maintaining our gut health. However, it is less known about biochemistry of members of this family by which they utilize non-cellulosic fiber in the gut. For enhancing this understanding, we studied that B. producta ATCC 27340 grew on arabinogalactan oligosaccharides (AGOs) as compared to polysaccharide form of arabinogalactan. Recombinant protein (Bp0469) was heterologously expressed in Escherichia coli BL21 (DE3) and revealed the optimum pH and temperature at 7.4 in phosphate buffer and 45 degrees C, respectively. Catalytic efficiency of recombinant Bp0469 for p-nitrophenyl (pNP)-alpha-L-arabinofuranoside was about half of pNP-13-D-galactopyranoside. It also cleaved natural substrates (lactose, arabinobiose and 3-O-(13-d-galactopyranosyl)-D-galactopyranose) and characterized AGOs in this study. Based on genomic, structural models, and biochemical characteristics, identified Bp0469 is a peculiar enzyme with two distinct domains that cleave alpha 1-5 linked arabinobiose and 13-D-Galp-1-3/4 linkages. Overall, the study enhances the knowledge on nutritional perspective of B. producta ATCC 27340 for thriving on non-cellulosic biomass, and identified enzyme can also be used for producing industrial important AGOs.

Automated summary

Human consumption of larch arabinogalactan enhances probiotic microflora and promotes the production of short-chain fatty acids in the gut. This study explores the biochemistry of a bacterial member of the Lachnospiraceae family, B. producta ATCC 27340, and identifies an enzyme (Bp0469) that plays a role in utilizing non-cellulosic fiber in the gut. The findings contribute to understanding the nutritional perspective of B. producta ATCC 27340 and its potential industrial applications in producing important arabinogalactan oligosaccharides (AGOs).