Metalloproteins and Bioenergetics
More than 50% of the predicted proteins are membrane-bound or metal containing, which just by itself shows the relevance of these types of proteins.
Head of Laboratory
ITQB Full Professor PhD in Chemistry, 1986, Universidade Nova de Lisboa | Research InterestsGroup MembersSelected PublicationsMetaloproteínas e Bioenergética (PT) | |
Phone (+351) 214469322 | |
Research Interests
More than 50% of the predicted proteins are membrane-bound or metal containing, which just by itself shows the relevance of these types of proteins. Therefore, the research on this laboratory is focused on prokaryotic i) membrane-bound proteins, aiming at understanding at the molecular level the functional role of metalloproteins in energy transduction, and ii) metalloenzymes, namely those involved in novel mechanisms of oxygen and nitric oxide detoxifi cation, quite relevant in host-pathogen interactions. The main target organisms are: sulfate reducers; facultative bacteria, e.g., E. coli and cyanobacteria, and extremophiles, which, mainly due to their phylogenetic distance from the most studied microbes, continuously reveal the presence of quite diverse and new proteins/enzymes, and allow a re-evaluation of several dogmas, by comparison with “canonical” enzymes, isolated from mitochondria and from the evolutionary related purple bacteria. These studies are now being extended to higher organisms, i.e., protozoa. The research involves a wide variety of complementary approaches: cell growth, protein chemistry, enzymatic assays, fast kinetics, spectroscopic studies (UV-Visible, Electron Paramagnetic Resonance, Resonance Raman), potentiometric and amperometric methods, reconstitution experiments in artifi cial liposomes, and a variety of ITQB and international collaborations for further complementary approaches. This reductionist approach, i.e., the in vitro studies of proteins, key players of the living world, is essential for the correct decoding of the genome sequences, and is being complemented to higher levels of organismal complexity by extensive collaborations with other laboratories. For 2006, several achievements were i) a detailed study of the molecular mechanism of 1Fe and 2Fe superoxide reductases and their physiological partners, which led to the proposal of a detailed mechanism for superoxide reduction to hydrogen peroxide; ii) the elucidation of the kinetics of the E. coli electron transfer chain that couples NADH oxidation to nitric oxide reduction to nitrous oxide; iii) a thorough and exhaustive characterisation by EPR spectroscopy coupled to potentiometric methods made for the fi rst time in an intact complex I; iv) a comprehensive redox study of several oxygen reductases members of different families of the haem-copper superfamily was undertaken, using a novel theoretical methodology. The thermodynamic parameters obtained are important to understand the coupling mechanism of the redox and chemical processes during oxygen reduction and proton pumping. Surprisingly, we observed that there is not a common behaviour present among all the studied enzymes; v) a new sub-family of proton-sodium antiporters was identified.
Group Members
- Manuela Pereira, Auxiliary Inv.
- Ana Melo, Assist. Prof. ULuso.
- Andreia Fernandes, Assist. Prof. UAlg.
- Smilja Todorovic, Post Doc
- Célia Romão, Post Doc
- Francesca Scandurra, PhD student
- João Vicente, PhD student
- Filipa Sousa, PhD student
- Andreia Veríssimo, PhD student
- Maxyme Cuypers, PhD student
- Vera Gonçalves, PhD student
- Ana Filipa Pinto, Undergraduate
- Cláudia Almeida, Technician
Selected Publications
- Rodrigues JV, Abreu IA, Cabelli D, Teixeira M. Superoxide reduction mechanism of Archaeoglobus fulgidus one-iron superoxide reductase Biochemistry. 2006 1;45(30):9266-78.
- Almeida CC, Romão CV, Lindley PF, Teixeira M, Saraiva LM. The Role of the Hybrid-Cluster Protein in Oxidative Stress Defense. (2006) J Biol Chem, 281: 32445-32450
- Electron Paramagnetic Resonance Studies of the Iron-Sulfur Centers from Complex I of Rhodothermus marinus. Fernandes AS, Sousa FL, Teixeira M, Pereira MM. (2006) Biochemistry Jan 24;45(3): 1002-8.
Laboratory's Website
For further information please visit the laboratory's website
Metaloproteínas e Bioenergética (PT)
Este laboratório procura compreender dois aspectos fundamentais dos sistemas vivos: a transformação e conservação de energia (Bioenergética), sem as quais não existiria vida, e a acção dos metais na vida (cerca de 30% das proteínas de qualquer organismo contêm iões metálicos). Estudamos essencialmente microrganismos pela sua importância no contexto do mundo vivo e, pela facilidade de manipulação, como modelos de organismos mais complexos. Processos tão importantes como o transporte de oxigénio, produção de monóxido de carbono ou óxido nítrico, controlo dos chamados “radicais livres” e a respiração ao nível molecular são realizados por proteínas com centros catalíticos contendo metais. As metaloproteínas estão ainda envolvidas na regulação da expressão de genes e são “sensores” de factores ambientais que desencadeiam múltiplos e complexos processos celulares As questões que pretendemos responder são de natureza dita fundamental mas as respostas poderão ter implicações práticas. Por exemplo, um elevadíssimo número de doenças resulta de defi ciências nos processos de conservação de energia ou no defi ciente controlo dos metais nos organismos. Na resposta a estas questões usamos uma abordagem multidisciplinar, desde a microbiologia, genética e bioquímica, até à utilização de múltiplas metodologias biofísicas.
