ITQB: PBFS - PhD Theses
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- PROTEIN FOLDING AND DISEASE THE MITOCHONDRIAL PROTEIN FRATAXINPublication . Correia, Ana Raquel Viegas; Gomes, CláudioThis dissertation focuses on the study of frataxin, a small mitochondrial protein whose deficiency is associated with the neurodegenerative disease Friedreich's ataxia (FRDA). Aiming at a better understanding of frataxin conformational and functional properties, two lines of research were followed: first, the effect of FRDA-related mutations in human frataxin (FXN) were studied and the role of oxidative stress related modification addressed; second, yeast frataxin (Yfh1) orthologue was used to explore the conformational and functional properties of the protein.(...)
- Protein stability in a proteomic perspectivePublication . Bozanic, Vesna; Gomes, CláudioThis work involved the identification and analysis of the properties of the most stable proteins present within proteomes, aiming at obtaining a general perspective of the factors that determine protein stability. As models we have focused on ensembles of proteins with high intrinsic stability, and for this purpose we have studied proteomes from the hyperthermophilic archaeon Sulfolobus solfataricus and Sulfurisphaera sp., whose properties were compared to those of the mesophilic bacterium Escherichia coli.(...)
- Metal ions and protein folding: conformational and functional interplayPublication . Botelho, Hugo M.; Gomes, Cláudio M.Metal ions are cofactors in about 30% of all proteins, where they fulfill catalytical and structural roles. Due to their unique chemistry and coordination properties they effectively expand the intrinsic polypeptide properties (by participating in catalysis or electron transfer reactions), stabilize protein conformations (like in zinc fingers) and mediate signal transduction (by promoting functionally relevant protein conformational changes). However, metal ions can also exert have deleterious effects in living systems by incorporating in non-native binding sites, promoting aberrant protein aggregation or mediating redox cycling with generation of reactive oxygen and nitrogen species. For this reason, the characterization of the roles of metal ions as modulators of protein conformation and stability provides fundamental knowledge on protein folding properties and is instrumental in establishing the molecular basis of disease. In this thesis we have analyzed protein folding processes using model protein systems incorporating covalently bound metal cofactors – iron-sulfur (FeS) proteins – or where metal ion binding is reversible and associated conformational readjustments – the S100 proteins.(...)
- Defective protein folding and function in metabolic disorders: studies on the mitochondrial flavoenzyme ETFPublication . Henriques, Bárbara J.; Gomes, Cláudio M.The work presented in this dissertation concerns the study of the electron transfer flavoprotein (ETF), a protein involved in mitochondrial β-oxidation whose deficiency is associated to multiple acyl-CoA dehydrogenase deficiency (MADD). The thesis will focus on establishing the functional, cellular and molecular consequences of the genetic variability in ETF, and in particular it aims to clarify the basis for the effect of heat stress on disease progression. Moreover, the beneficial effects of vitamin B2 supplementation will be addressed.(...)
- Protein folding, metal ions and conformational states: the case of a di-cluster ferredoxinPublication . Leal, Sónia S.; Gomes, Cláudio M.Metal ions are present in over thirty percent of known proteins. Apart from a well established function in catalysis and electron transfer, metals and metal centres are also important structural elements which may as well play a key role in modulating protein folding and stability. In this respect, cofactors can act not only as local structural stabilizing elements in the native state, contributing to the maintenance of a given specific structural fold, but may also function as potential nucleation points during the protein folding process...