The enzymes work via a distinct substrate-assisted mechanism that utilizes the 2-acetamido group as nucleophile.
Application Multiple Sequence Alignment Download View PublicationDownload View publication Copy reference Copy caption Embed figure Multiple sequence alignment of AvHex catalytic domain (Query) with solved crystal structures of catalytic domains of -N-acetylhexosaminidases from various sources performed with Esprint 3.0 (Robert and Gouet 2014) and Jalview (Clamp et al.Active-site amino acids are marked by black dots and labeled according to AvHex numeration.
Residues with identities higher than 30 for a particular site are colored by ClustalX coloring scheme, which groups residues according to similar properties by selected color: G; P; positively charged K, R; Y, H; negatively charged D, E; polar Q, N, S, T; hydrophobic L, V, M, A, I, W, C, F. Secondary structure elements are based on the 5OAR structure and defined by symbols and letters as -alpha helix or -beta sheet. The long loops HL1 and HL2 conserved in fungal -N-acetylhexosaminidases are labeled; their ends are marked by Source publication 2 Selective -N-acetylhexosaminidase from Aspergillus versicolora tool for producing bioactive carbohydrates Article Full-text available Feb 2019 Pavla Bojarov Natallia Kulik Kristna Slmov. Vladimr Ken -N-Acetylhexosaminidases (EC 3.2.1.52) are typical of their dual activity encompassing both N-acetylglucosamine and N-acetylgalactosamine substrates. Here we present the isolation and characterization of a selective -N-acetylhexosaminidase from the fungal strain of Aspergillus versicolor. These multivalent rhamnose carrying structures can be used in search for rhamnose-specific lectins and in biological assays for testing inhibitory activities towards AGE-mediated pathologies. The trivalent carrier 24 was synthesized as described previously 28. Two of the prepared transglycosylation products, rutinosyl azide (11) and 2-azidoethyl rutinoside (12), were used as possible ligands for multivalent presentation.. Dual Substrate Specificity of the Rutinosidase from Aspergillus niger and the Role of Its Substrate Tunnel Article Full-text available Aug 2020 INT J MOL SCI Katerina Brodsky Michal Kut Helena Pelantov Josef Cvaka Pavla Bojarov Rutinosidases (-l-rhamnopyranosyl-(1-6)--d-glucopyranosidases, EC 3.2.1.168, CAZy GH5) are diglycosidases that cleave the glycosidic bond between the disaccharide rutinose and the respective aglycone. Application Multiple Sequence Alignment Free OH GroupSimilar to many retaining glycosidases, rutinosidases can also transfer the rutinosyl moiety onto acceptors with a free OH group (so-called transglycosylation). The recombinant rutinosidase from Aspergillus niger (AnRut) is selectively produced in Pichia pastoris. It can catalyze transglycosylation reactions as an unpurified preparation directly from cultivation. This enzyme exhibits catalytic activity towards two substrates; in addition to rutinosidase activity, it also exhibits -d-glucopyranosidase activity. As a result, new compounds are formed by -glucosylation or rutinosylation of acceptors such as alcohols or strong inorganic nucleophiles (NaN3). Transglycosylation products with aliphatic aglycones are resistant towards cleavage by rutinosidase, therefore, their side hydrolysis does not occur, allowing higher transglycosylation yields. ![]() Interactions between the transglycosylation products and the recombinant AnRut were analyzed by molecular modeling. We revealed the role of a substrate tunnel in the structure of AnRut, which explained the unusual catalytic properties of this glycosidase and its specific transglycosylation potential. AnRut is attractive for biosynthetic applications, especially for the use of inexpensive substrates (rutin and isoquercitrin). View. However, whereas other hydrolytic enzymes such as proteases, esterases, or lipases can cope with even non-aqueous systems (aw 96 97100,101,103104105106115,116,118119120... In general, the most commonly added co-solvent in glycosidase-catalyzed trans-glycosylation reactions is dimethylsulfoxide (DMSO) as it is often required to dissolve the pNP-activated donor substrate. However, there are only a few studies, in which DMSO (5-20 (vv)) has been present during GH20-catalyzed trans-glycosylation (Tables 5,9 and 10) 24,101,103104105. Especially for the fungal enzymes it seems to be more common to add acetonitrile (MeCN, 5-45 (vv)) as co-solvent to increase yields (Tables 2-4 and 10) 54,56,61,88,90919295 96 97. Meyer Birgitte Zeuner -N-acetylhexosaminidases (EC 3.2.1.52) are retaining hydrolases of glycoside hydrolase family 20 (GH20). These enzymes catalyze hydrolysis of terminal, non-reducing N-acetylhexosamine residues, notably N-acetylglucosamine or N-acetylgalactosamine, in N-acetyl--D-hexosaminides. In nature, bacterial -N-acetylhexosaminidases are mainly involved in cell wall peptidoglycan synthesis, analogously, fungal -N-acetylhexosaminidases act on cell wall chitin.
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