Bioengineering / Biyomühendislik
Permanent URI for this collectionhttps://hdl.handle.net/11147/4529
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Article Citation - WoS: 6Citation - Scopus: 6Functional Characterization of a Novel Cyp119 Variant To Explore Its Biocatalytic Potential(Wiley, 2021) Sürmeli, Nur Başak; Sürmeli, Nur Başak; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyBiocatalysts are increasingly applied in the pharmaceutical and chemical industry. Cytochrome P450 enzymes (P450s) are valuable biocatalysts due to their ability to hydroxylate unactivated carbon atoms using molecular oxygen. P450s catalyze reactions using nicotinamide adenine dinucleotide phosphate (NAD(P)H) cofactor and electron transfer proteins. Alternatively, P450s can utilize hydrogen peroxide (H2O2) as an oxidant, but this pathway is inefficient. P450s that show higher efficiency with peroxides are sought after in industrial applications. P450s from thermophilic organisms have more potential applications as they are stable toward high temperature, high and low pH, and organic solvents. CYP119 is an acidothermophilic P450 from Sulfolobus acidocaldarius. In our previous study, a novel T213R/T214I (double mutant [DM]) variant of CYP119 was obtained by screening a mutant library for higher peroxidation activity utilizing H2O2. Here, we characterized the substrate scope; stability toward peroxides; and temperature and organic solvent tolerance of DM CYP119 to identify its potential as an industrial biocatalyst. DM CYP119 displayed higher stability than wild-type (WT) CYP119 toward organic peroxides. It shows higher peroxidation activity for non-natural substrates and higher affinity for progesterone and other bioactive potential substrates compared to WT CYP119. DM CYP119 emerges as a new biocatalyst with a wide range of potential applications in the pharmaceutical and chemical industry.Article Citation - WoS: 13Citation - Scopus: 13Solid-Binding Peptide-Guided Spatially Directed Immobilization of Kinetically Matched Enzyme Cascades in Membrane Nanoreactors(American Chemical Society, 2021) Yücesoy, Deniz Tanıl; Yücesoy, Deniz Tanıl; Akkineni, Susrut; Tamerler, Candan; Hinds, Bruce J.; Sarıkaya, Mehmet; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyBiocatalysis is a useful strategy for sustainable green synthesis of fine chemicals due to its high catalytic rate, reaction specificity, and operation under ambient conditions. Addressable immobilization of enzymes onto solid supports for one-pot multistep biocatalysis, however, remains a major challenge. In natural pathways, enzymes are spatially coupled to prevent side reactions, eradicate inhibitory products, and channel metabolites sequentially from one enzyme to another. Construction of a modular immobilization platform enabling spatially directed assembly of multiple biocatalysts would, therefore, not only allow the development of high-efficiency bioreactors but also provide novel synthetic routes for chemical synthesis. In this study, we developed a modular cascade flow reactor using a generalizable solid-binding peptide-directed immobilization strategy that allows selective immobilization of fusion enzymes on anodic aluminum oxide (AAO) monoliths with high positional precision. Here, the lactate dehydrogenase and formate dehydrogenase enzymes were fused with substrate-specific peptides to facilitate their self-immobilization through the membrane channels in cascade geometry. Using this cascade model, two-step biocatalytic production of l-lactate is demonstrated with concomitant regeneration of soluble nicotinamide adenine dinucleotide (NADH). Both fusion enzymes retained their catalytic activity upon immobilization, suggesting their optimal display on the support surface. The 85% cascading reaction efficiency was achieved at a flow rate that kinetically matches the residence time of the slowest enzyme. In addition, 84% of initial catalytic activity was preserved after 10 days of continuous operation at room temperature. The peptide-directed modular approach described herein is a highly effective strategy to control surface orientation, spatial localization, and loading of multiple enzymes on solid supports. The implications of this work provide insight for the single-step construction of high-power cascadic devices by enabling co-expression, purification, and immobilization of a variety of engineered fusion enzymes on patterned surfaces. © 2021 The Authors. Published by American Chemical Society.Article Citation - WoS: 3Citation - Scopus: 5A Novel Thermophilic Hemoprotein Scaffold for Rational Design of Biocatalysts(Springer Verlag, 2018) Efua Aggrey Fynn, Joana; Sürmeli, Nur Başak; Sürmeli, Nur Başak; 03.01. Department of Bioengineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyHemoproteins are commonly found in nature, and involved in many important cellular processes such as oxygen transport, electron transfer, and catalysis. Rational design of hemoproteins can not only inspire novel biocatalysts but will also lead to a better understanding of structure-function relationships in native hemoproteins. Here, the heme nitric oxide/oxygen-binding protein from Caldanaerobacter subterraneus subsp. tengcongensis (TtH-NOX) is used as a novel scaffold for oxidation biocatalyst design. We show that signaling protein TtH-NOX can be reengineered to catalyze H2O2 decomposition and oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) by H2O2. In addition, the role of the distal tyrosine (Tyr140) in catalysis is investigated. The mutation of Tyr140 to alanine hinders the catalysis of the oxidation reactions. On the other hand, the mutation of Tyr140 to histidine, which is commonly observed in peroxidases, leads to a significant increase of the catalytic activity. Taken together, these results show that, while the distal histidine plays an important role in hemoprotein reactions with H2O2, it is not always essential for oxidation activity. We show that TtH-NOX protein can be used as an alternative scaffold for the design of novel biocatalysts with desired reactivity or functionality. H-NOX proteins are homologous to the nitric oxide sensor soluble guanylate cyclase. Here, we show that the gas sensor protein TtH-NOX shows limited capacity for catalysis of redox reactions and it can be used as a novel scaffold in biocatalysis design. [GRAPHICS] .