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Engineering A-type Dye-Decolorizing Peroxidases by Modification of a Conserved Glutamate Residue
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Orientador(es)
Resumo(s)
Dye-decolorizing peroxidases (DyPs) are recently identified microbial enzymes that have been used in several Biotechnology applications from wastewater treatment to lignin valorization. However, their properties and mechanism of action still have many open questions. Their heme-containing active site is buried by three conserved flexible loops with a putative role in modulating substrate access and enzyme catalysis. Here, we investigated the role of a conserved glutamate residue in stabilizing interactions in loop 2 of A-type DyPs. First, we did site saturation mutagenesis of this residue, replacing it with all possible amino acids in bacterial DyPs from Bacillus subtilis (BsDyP) and from Kitasatospora aureofaciens (KaDyP1), the latter being characterized here for the first time. We screened the resulting libraries of variants for activity towards ABTS and identified variants with increased catalytic efficiency. The selected variants were purified and characterized for activity and stability. We furthermore used Molecular Dynamics simulations to rationalize the increased catalytic efficiency and found that the main reason is the electron channeling becoming easier from surface-exposed tryptophans. Based on our findings, we also propose that this glutamate could work as a pH switch in the wild-type enzyme, preventing intracellular damage.
Descrição
Funding Information: . Financial support by the Austrian Science Fund (FWF) through the doctoral program Biomolecular Technology of Proteins (BioToP, grant number W1224), the Austrian Federal Ministry for Digital and Economic Affairs, the National Foundation for Research, Technology and Development, the Christian Doppler Research Association, Funda\u00E7\u00E3o para a Ci\u00EAncia e Tecnologia (FCT), Portugal, grants FCT 2022.02027.PTDC, MOSTMICRO\u2010ITQB (UIDB/04612/2020 and UIDP/04612/2020), LS4FUTURE (LA/P/0087/2020) are gratefully acknowledged Publisher Copyright: © 2024 The Authors. ChemBioChem published by Wiley-VCH GmbH.
Palavras-chave
Enzymes Oxidoreductases Protein engineering Protein structures Strucutre-activity relationship Biochemistry Molecular Medicine Molecular Biology Organic Chemistry