Unravelling the carbohydrate specificity of MelA from Lactobacillus plantarum WCFS1: An α-galactosidase displaying regioselective transgalactosylation

This comprehensive work addresses, for the first time, the heterologous production, purification, biochemical characterization and carbohydrate specificity of MelA, a cold-active α-galactosidase belonging to the Glycoside Hydrolase family 36, from the probiotic organism Lactobacillus plantarum WCFS1. The hydrolytic activity of MelA α-galactosidase on a wide range of p-nitrophenyl glycoside derivatives and carbohydrates of different molecular-weights showed its high selectivity and efficiency towards the α(1 → 6) glycosidic bonds involving the anomeric carbon of galactose and the C6-hydroxyl group of galactose or glucose units. MelA α-galactosidase also presented a high regioselectivity, efficiency and diversity in accommodating donor and acceptor substrates for the synthesis of α-GOS through transgalactosylation reactions. The catalytic mechanism of MelA for the production of α-GOS was elucidated, revealing its great preference for the transfer of galactosyl residues to the C6-hydroxyl group of galactose units to elongate the chain of α-GOS having either a terminal sucrose (raffinose family oligosaccharides, RFOS) or a terminal glucose (melibiose, manninotriose and verbascotetraose). Our findings indicate the feasibility of using MelA α-galactosidase from Lactobacillus plantarum WCFS1 in the hydrolysis of RFOS and in the efficient and versatile synthesis of α-GOS with appealing functional properties in the context of food and nutraceutical applications.

Bibliographic Details

Main Authors:	Delgado, Paloma, Plaza-Vinuesa, Laura, Hernández-Hernández, Oswaldo, Rivas, Blanca de las, Corzo, Nieves, Muñoz, Rosario, Moreno, F. Javier
Other Authors:	Ministerio de Economía, Industria y Competitividad (España)
Format:	artículo biblioteca
Published:	Elsevier 2020
Subjects:	α-Galactosidase, Lactobacillus plantarum WCFS1, Prebiotics,
Online Access:	http://hdl.handle.net/10261/203889 http://dx.doi.org/10.13039/501100011033 http://dx.doi.org/10.13039/501100010198
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