Proteins are responsible of a very large number of biological functions in living systems. Among them enzymes are the catalysts in biological sytems. Their properties are strongly affected by their three-dimensional structure. Enzymes often contain transition metal ions which are involved in the reaction catalysed by the enzyme. The understanding of the functional behaviour of enzymes is linked to the knowledge of their three-dimensional structure.
There are different methods to analyse the structure of enzymes, by single crystal X-ray structure analysis or by multidimensional NMR techniques using the NOEs. The NMR analysis provides the structure of the proteins in a medium of biological interest, dissolved in water.
The NMR analysis normally only allows the characterization of small enzymes. In nature there are a lot of enzymes which contain paramagnetic transition metals in their active site. The paramagnetism of these enzymes, even if they are large, allows the study of the active site of these enzymes via the paramagnetic shift in their obtained NMR spectra. Targets of the project are the structural determinations of paramagnetic metalloproteins as cytochromes containing one or more iron atoms or at least to get a view of their active sites using multidimensional NMR techniques.
The change of the oxidation state of the transition metal atoms in the enzymes may cause differences in their solution structure which may be determined using these methods. So it should be possible to understand the functional behaviour of these redox active enzymes.