ITQB: MET - MA Dissertations
URI permanente para esta coleção:
Navegar
Entradas recentes
- Insight into the biophysical properties of AsP2Ox, a candidate enzyme for health diagnosis biosensorsPublication . Frazão, Tomás; Borges, Patrícia; Martins, Lígia"Pyranose-2-oxidases (P2Oxs) are flavoenzymes capable of oxidizing a wide range of sugars, in particular D-glucose, with concomitant reduction of molecular oxygen to hydrogen peroxide. The vast majority of P2Oxs were identified in fungi, but recently, bacterial P2Oxs were characterized showing distinctive and interesting properties to be explored in biotechnology. This work aims to unveil structural details of the bacterial P2Ox from Pseudoarthrobacter siccitolerans (AsP2Ox). Protein crystals were obtained in space group C2221 space group and diffracted X-rays to a resolution of 2.01 Å, and a crystal structure of the AsP2Ox-Glucose complex at 2.35 Å resolution was also obtained. The typical P2Oxs substrate and FAD-binding domains were identified, and a flexible loop (substrate loop) found in fungal P2Oxs with a role of gating and accommodating the substrate in the active site is also present in AsP2Ox.(...)"
- Liquid Effluent Bioremediation Resorting to Microalgae CultivationPublication . Fernandes, Joana Batista Nunes; Martins, Lígia; Badenes, Sara; Cardoso, Pedro"Agricultural and industrial activities require extensive use of raw materials and generate large amounts of nutrient-rich waste streams. These have been linked to a drastic and widespread increase in the pollution of aquatic systems, and incidence of eutrophication events. The need to reduce nutrient runoffs and preserve the presently available water resources is a major concern and a great opportunity to develop nutrient removal and recovery processes for waste streams. Microalgae have been exploited for the treatment of different industrial wastewaters, coupling microalgal biomass production with resource recovery and waste valorisation, demonstrating the potential of microalgal-based systems to integrate a circular economy model.(...)"
- Laboratory Evolution of New Bacterial Galactose Oxidases for Green Biotech ApplicationsPublication . Dias, Carolina Gomes Ferreira"Galactose oxidases (GalOxs) are copper radical oxidases (CROs) that catalyze the oxidation of primary alcohols to the corresponding aldehydes, reducing molecular oxygen to hydrogen peroxide. These monomeric metalloenzymes have a copper ion as a cofactor and are secreted by filamentous fungi, with FgrGalOx being the best-studied representative. GalOxs holds potential for various biotechnological applications in small molecule synthesis, oxygen removal, and biosensors. Therefore, a better understanding of GalOx from different organisms is crucial, as it may reveal novel or improved properties to be explored in various fields. This work unravels the properties of a new bacterial galactose oxidase, AsGalOx, from Pseudoarthrobacter siccitolerans while simultaneously tailoring its properties through enzyme engineering approaches.(...)"
- Improving a bacterial pyranose 2-oxidase from Arthrobacter siccitolerans through directed evolutionPublication . Santos, Diana Marisa Marques dos; Martins, Lígia"Pyranose 2-oxidases (P2Ox) are flavoproteins that catalyze the oxidation of several aldopyranoses to yield the corresponding 2-keto-aldoses with concomitant reduction of O2 to H2O2 and are enzymes that show many biotechnological applications. Recently, a bacterial P2Ox from Arthrobacter siccitolerans (AsP2Ox) was characterized for the first time since bacteria grow faster as compared to fungi and have well-established genetic and molecular biological tools allowing for higher enzyme production yields. Directed evolution has proven to be a powerful approach to improve enzyme efficiency and robustness required for biotechnological applications. Therefore, in this work the optimization and validation of critical steps of directed evolution was performed, namely mutagenesis protocols, cell growth, lysis and high-throughput enzymatic assays. One round of evolution through error prone PCR was performed and a total of 25 000 clones were screened to find variants with improved activity for D-glucose and dioxygen. One hit variant, 2C9, was identified, showing higher activity than wild-type and containing two non-synonymous (A35T and F300V) and one synonymous mutation (Q343Q).(...)."