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Multiheme c-type cytochromes from members of the Desulfovibrionacea and Geobactereacea families play crucial roles in the bioenergetics of these microorganisms. Thermodynamic studies using NMR and visible spectroscopic techniques on tetraheme cytochromes c3 isolated from Desulfovibrio spp. and more recently on a triheme cytochrome from Geobacter sulfurreducens showed that the properties of each redox centre are modulated by the neighbouring redox centres enabling these proteins to perform energy transduction and thus contributing to cellular energy conservation. Electron/proton transfer coupling relies on redox-linked conformational changes that were addressed for some multiheme cytochromes from the comparison of protein structure of fully reduced and fully oxidised forms. In this work, we identify for the first time in a multiheme cytochrome the simultaneous presence of two different conformations in solution. This was achieved by probing the different oxidation stages of a triheme cytochrome isolated from G. sulfurreducens using 2D-NMR techniques. The results presented here will be the foundations to evaluate the modulation of the redox centres properties by conformational changes that occur during the reoxidation of a multiheme protein.

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Molybdenum and tungsten are found in biological systems in a mononuclear form in the active site of a diverse group of enzymes that generally catalyze oxygen-atom-transfer reactions. The metal atom (Mo or W) is coordinated to one or two pyranopterin molecules and to a variable number of ligands such as oxygen (oxo, hydroxo, water, serine, aspartic acid), sulfur (cysteines), and selenium (selenocysteines) atoms. In addition, these proteins contain redox cofactors such as iron-sulfur clusters and heme groups. All of these metal cofactors are along an electron-transfer pathway that mediates the electron exchange between substrate and an external electron acceptor (for oxidative reactions) or donor (for reductive reactions). We describe in this Account a combination of structural and electronic paramagnetic resonance studies that were used to reveal distinct aspects of these enzymes.

The relationship between the changes of the global economy and individual working conditions formed the background of the first WORKS conference “The transformation of work in a global knowledge economy: towards a conceptual framework”, held in Chania, Greece from 21st – 22nd September, 2006 and attended by around 50 European researchers. Experts from academia and trade unions from all over the world were invited to give insights into their field of research, contributing to one of the main topics of the conference: (i) globalisation and organisational restructuring, (ii) workers’ organisation, the quality of working life and the gender dimension and (iii) global experiences and recommendations.

Nitrogen is a vital component in living organisms as it participates in the making of essential biomolecules such as proteins, nucleic acids, etc. In the biosphere, nitrogen cycles between the oxidation states +V and -III producing many species that constitute the biogeochemical cycle of nitrogen. All reductive branches of this cycle involve the conversion of nitrate to nitrite, which is catalyzed by the enzyme nitrate reductase. The characterization of nitrate reductases from prokaryotic organisms has allowed us to gain considerable information on the molecular basis of nitrate reduction. Prokaryotic nitrate reductases are mononuclear Mo-containing enzymes sub-grouped as respiratory nitrate reductases, periplasmic nitrate reductases and assimilatory nitrate reductases. We review here the biological and molecular properties of these three enzymes along with their gene organization and expression, which are necessary to understand the biological processes involved in nitrate reduction.

This report begins with some general information and analysis of policy and regulation that were the subjects of discussion and exchange in the policy pillar in the first phase of WORKS. The second section is a synthesis of country information on general principles and trends of policy and policy enforcement. This is followed by a summary of sector information for the sectors chosen by the qualitative pillar to be the objects of empirical analysis. The last summarises research questions and dimensions to be guidelines for carrying out case studies and capturing the relevance and effects of policy and institutions at the workplace. –

This report begins with some general information and analysis of policy and regulation that were the subjects of discussion and exchange in the policy pillar in the first phase of WORKS. The second section is a synthesis of country information on general principles and trends of policy and policy enforcement. This is followed by a summary of sector information for the sectors chosen by the qualitative pillar to be the objects of empirical analysis. The last summarises research questions and dimensions to be guidelines for carrying out case studies and capturing the relevance and effects of policy and institutions at the workplace.