| Autor: |
Méndez-Líter JA; Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain., Pozo-Rodríguez A; Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain., Madruga E; Centro de Investigaciones Biológicas Margarita Salas, Department of Structural and Chemical Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain., Rubert M; Department of Biochemistry and Molecular Biology, School of Biology, Instituto de Investigación Hospital 12 de Octubre, Universidad Complutense de Madrid, C/de José Antonio Nováis 12, 28040 Madrid, Spain., Santana AG; Department of Bioorganic Chemistry, Instituto de Química Orgánica General, Spanish National Research Council (CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain., de Eugenio LI; Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain., Sánchez C; Department of Biochemistry and Molecular Biology, School of Biology, Instituto de Investigación Hospital 12 de Octubre, Universidad Complutense de Madrid, C/de José Antonio Nováis 12, 28040 Madrid, Spain., Martínez A; Centro de Investigaciones Biológicas Margarita Salas, Department of Structural and Chemical Biology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain., Prieto A; Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain., Martínez MJ; Centro de Investigaciones Biológicas Margarita Salas, Department of Microbial and Plant Biotechnology, Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain. |
| Abstrakt: |
Glycoside hydrolases (GHs) are enzymes that hydrolyze glycosidic bonds, but some of them can also catalyze the synthesis of glycosides by transglycosylation. However, the yields of this reaction are generally low since the glycosides formed end up being hydrolyzed by these same enzymes. For this reason, mutagenic variants with null or drastically reduced hydrolytic activity have been developed, thus enhancing their synthetic ability. Two mutagenic variants, a glycosynthase engineered from a β-glucosidase (BGL-1-E521G) and a thioglycoligase from a β-xylosidase (BxTW1-E495A), both from the ascomycete Talaromyces amestolkiae , were used to synthesize three novel epigallocatechin gallate (EGCG) glycosides. EGCG is a phenolic compound from green tea known for its antioxidant effects and therapeutic benefits, whose glycosylation could increase its bioavailability and improve its bioactive properties. The glycosynthase BGL-1-E521G produced a β-glucoside and a β-sophoroside of EGCG, while the thioglycoligase BxTW1-E495A formed the β-xyloside of EGCG. Glycosylation occurred in the 5″ and 4″ positions of EGCG, respectively. In this work, the reaction conditions for glycosides' production were optimized, achieving around 90% conversion of EGCG with BGL-1-E521G and 60% with BxTW1-E495A. The glycosylation of EGCG caused a slight loss of its antioxidant capacity but notably increased its solubility (between 23 and 44 times) and, in the case of glucoside, also improved its thermal stability. All three glycosides showed better antiproliferative properties on breast adenocarcinoma cell line MDA-MB-231 than EGCG, and the glucosylated and sophorylated derivatives induced higher neuroprotection, increasing the viability of SH-S5Y5 neurons exposed to okadaic acid. |
