Dual 6Pβ-Galactosidase/6Pβ-Glucosidase GH1 Family for Lactose Metabolism in the Probiotic Bacterium Lactiplantibacillus plantarum WCFS1

Abstract

Intestinal lactic acid bacteria can help alleviate lactose maldigestion by promoting lactose hydrolysis in the small intestine. This study shows that protein extracts from probiotic bacterium Lactiplantibacillus plantarum WCFS1 possess two metabolic pathways for lactose metabolism, involving β-galactosidase (β-gal) and 6Pβ-galactosidase (6Pβ-gal) activities. As L. plantarum WCFS1 genome lacks a putative 6Pβ-gal gene, the 11 GH1 family proteins, in which their 6Pβ-glucosidase (6Pβ-glc) activity was experimentally demonstrated,, were assayed for 6Pβ-gal activity. Among them, only Lp_3525 (Pbg9) also exhibited a high 6Pβ-gal activity. The sequence comparison of this dual 6Pβ-gal/6Pβ-glc GH1 protein to previously described dual GH1 proteins revealed that L. plantarum WCFS1 Lp_3525 belonged to a new group of dual 6Pβ-gal/6Pβ-glc GH1 proteins, as it possessed conserved residues and structural motifs mainly present in 6Pβ-glc GH1 proteins. Finally, Lp_3525 exhibited, under intestinal conditions, an adequate 6Pβ-gal activity with possible relevance for lactose maldigestion management.

Identification of a Novel Lactose-Specific PTS Operon in Bacillus licheniformis and Development of Derivative Artificial Operon Modules

“…In general, 6-phospho-β-galactosidase was classified into the GH1 family. Although some GH1 family-derived 6-phospho-β-glucosidases perform 6-phospho-β-galactosidase functions, ,,, phylogenetic tree analysis revealed that LacD is not highly homologous to them (Figure B). Therefore, LacD is a unique 6-phospho-β-galactosidase of the GH4 family.…”

“…Lactose is a disaccharide that is important for milk and its derivatives. 1 It poses health concerns for individuals with lactose intolerance, 2 leading to its disposal during dairy production and subsequent environmental contamination. As the utilization of lactose has become one of the focal points of current research, 3 understanding the molecular mechanisms underlying lactose metabolism is vital.…”

“…Lactose is a disaccharide that is important for milk and its derivatives . It poses health concerns for individuals with lactose intolerance, leading to its disposal during dairy production and subsequent environmental contamination.…”

Characterization and stabilization of GluLm and its application to deglycosylate dietary flavonoids and lignans

“…However, unlike GH3 β-glucosidases mentioned in Fig. 1 , GluLm exhibited a broad range of optimal temperatures and pHs (Florindo et al 2018 ; Lee et al 2011 ; Matsumoto et al 2015 ; Michlmayr et al 2009 ; Michlmayr et al 2010 ; Yan et al 2018 ), similarly to other glycosyl hydrolases explored, such as Pgb4 and Pgb6 from L. plantarum (Plaza-Vinuesa et al 2022 ; Plaza-Vinuesa et al 2023 ). Only in terms of pH, Blon0625 from B. longum subsp .…”

“…Although recently it has been described the absence of β-glucosidase activity on L. plantarum (Plaza-Vinuesa et al 2022 , 2023 ), this strain is able to transform oleuropein into its aglycone (Landete et al 2008 ; Michlmayr and Kneifel 2014 ), probably due to the presence of several intracellular phospho-β-glucosidases (Plaza-Vinuesa et al 2022 , 2023 ). However, since these enzymes require phosphorylated substrates, from an industrial point of view, the application of β-glucosidases such as GluLm would be much convenient to obtain the more bioavailable oleuropein aglycone, since it would avoid the cost of the prior phosphorylation of oleuropein.…”