Glicosidasas como herramientas para la diversificación estructural de moléculas bioactivas
Glycosidases constitute a diverse group of enzymes that catalyze the hydrolysis of glycosidic bonds, thus releasing the sugar or modifying the structure of the original substrate. In addition to hydrolysis, some glycosidases are also capable of catalyzing transglycosylation reactions. In this proces...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
| Publicado: |
Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica
2024
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=posgraafa&cl=CL1&d=HWA_7844 https://repositoriouba.sisbi.uba.ar/gsdl/collect/posgraafa/index/assoc/HWA_7844.dir/7844.PDF |
| Aporte de: |
| Sumario: | Glycosidases constitute a diverse group of enzymes that catalyze the hydrolysis of glycosidic
bonds, thus releasing the sugar or modifying the structure of the original substrate. In addition
to hydrolysis, some glycosidases are also capable of catalyzing transglycosylation reactions. In
this process, sugar is transferred from a sugar donor substrate to a different nucleophilic
acceptor other than water, thereby forming a new glycosidic bond. Both activities have various
biotechnological applications that are constantly expanding.
In this work, we studied bacterial and fungal glycosidases using a biochemical approach
combined with the exploration of genomes sequenced by our laboratory and available in public
databases (genome mining). The bacterium Actinoplanes missouriensis 431T and the fungus
Aspergillus alliaceus DSM 813 were the central microorganisms of the study. Genomic context
analysis of the gene encoding ?R?G diglycosidase from A. missouriensis 431T (BAL86042.1)
revealed the presence of an ?-L-rhamnosidase under the same transcriptional regulator. This
genetic pattern was also identified in five strains of the Actinoplanes genus, allowing us to
propose a catabolic pathway for hesperidin hydrolysis and subsequent utilization of the
monosaccharides. In contrast, induction studies by flavonoids (naringin, rutin) in A. alliaceus
DSM 813 revealed a preferential pathway of sequential deglycosylation involving an ?-
rhamnosidase and ?-glucosidase.
Recombinant enzymes and commercial enzymatic preparations were used in the synthesis
of value-added compounds (hesperetin 7-O-glucoside, rutinose, 4-nitrophenyl ?-rutinoside, and
glyceryl rutinoside). The compound synthesized by the ?-L-rhamnosidase of A. missourensis
431T, hesperetin 7-O-glucoside, was used in the study of regiospecificity of the ?R?G I
diglycosidase from Acremonium sp. DSM 24697, allowing the detection for the first time of
monoglucosidase activity of this enzyme. It is noteworthy that hesperetin 7-O-glucoside is the
glucosidic derivative of the substrate with the highest specificity for ?R?G I, hesperidin.
Subsequently, by engineering the reaction medium, the selectivity of the commercial enzymatic
cocktail AromaseTM H2 glycosidase mixture was directed, allowing the development of selective
processes for rutinose production and synthesis of 4-nitrophenol ?-rutinoside. Finally, a
bioprocess was developed for the synthesis and purification of glyceryl rutinoside with the ?R?G
I enzyme from Acremonium sp. DSM 24697. Glycerol and citrus fruit processing residue were
used as glycosidic donor substrates, proposing an alternative in the biorefinery of these fruits. |
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