- A Mechanism-Based Approach to Screening Metagenomic Libraries for Discovery of Unconventional Glycosidases
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Functional metagenomics has opened new opportunities for enzyme discovery. To exploit the full potential of this new tool, the design of selective screens is essential, especially when searching for rare enzymes. To identify novel glycosidases that employ cleavage strategies other than the conventional Koshland mechanisms, a suitable screen was needed. Focusing on the unsaturated glucuronidases (UGLs), it was found that use of simple aryl glycoside substrates did not allow sufficient discrimination against β-glucuronidases, which are widespread in bacteria. While conventional glycosidases cannot generally hydrolyze thioglycosides efficiently, UGLs follow a distinct mechanism that allows them to do so. Thus, fluorogenic thioglycoside substrates featuring thiol-based self-immolative linkers were synthesized and assessed as selective substrates. The generality of the approach was validated with another family of unconventional glycosidases, the GH4 enzymes. Finally, the utility of these substrates was tested by screening a small metagenomic library.
- Nasseri, Seyed Amirhossein,Betschart, Leo,Opaleva, Daria,Rahfeld, Peter,Withers, Stephen G.
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supporting information
p. 11359 - 11364
(2018/08/28)
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- Chromogenic carbamate and acetal substrates for glycosaminidases
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The enzyme Dispersin B is a medicinally relevant β-hexosaminidase with potential for use in the treatment of biofilm-related infections. Here we describe the synthesis and evaluation of a p-nitrophenyl glycosyl carbamate and a p-nitrophenyl glycosyl aceta
- Chibba, Anthony,Dasgupta, Somnath,Yakandawala, Nandadeva,Madhyastha, Srinivasa,Nitz, Mark
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p. 549 - 558
(2012/06/01)
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- Reaction of Phenols with t-Butyl Bromide-Dimethyl Sulphoxide. Methylthiomethylation versus Bromination
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t-Butyl bromide-activated dimethyl sulphoxide reacts with phenols to give either methylthiomethylation or bromination products.Several equilibria are shown to be simultaneously present in the system; however, by appropriate choice of several parameters (basicity, temperature, and reactant ratio) it is possible to drive the reaction selectively in one direction.A general discussion on the mechanism of these reactions is given.
- Dossena, Arnaldo,Marchelli, Rosangela,Casnati, Giuseppe
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p. 1141 - 1144
(2007/10/02)
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