PDF(Pubmed)
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.
摘要：
肠道乳酸菌可以通过促进小肠中的乳糖水解来帮助缓解乳糖消化不良。这项研究表明，来自益生菌植物乳杆菌WCFS1的蛋白质提取物具有两种乳糖代谢途径，涉及β-半乳糖苷酶（β-gal）和6Pβ-半乳糖苷酶（6Pβ-gal）活性。由于植物乳杆菌WCFS1基因组缺乏推定的6Pβ-gal基因，11个GH1家族蛋白，其中通过实验证明了它们的6Pβ-葡萄糖苷酶（6Pβ-glc）活性，,测定6Pβ-gal活性。其中,只有Lp_3525(Pbg9)也表现出高的6Pβ-gal活性。这种双重6Pβ-gal/6Pβ-glcGH1蛋白与先前描述的双重GH1蛋白的序列比较表明，植物乳杆菌WCFS1Lp_3525属于一类新的双重6Pβ-gal/6Pβ-glcGH1蛋白，因为它具有保守的残基和结构基序，主要存在于6Pβ-glcGH1蛋白中。最后,Lp_3525已展出，在肠道条件下，足够的6Pβ-gal活性与乳糖消化不良管理可能相关。
