Our project is centered on an investigation of the properties of the haem group, which is the reactive center (prosthetic group) of the haemoglobin protein. Despite its wide biological importance, no study in the past has been able to elucidate the molecular mechanisms underlying the activity of the most important proteins carrying the haem group. Our study will be performed with a computational method (the CarParrinello scheme) that allows now to treat molecules of the size of the haem group and to investigate the interplay of structural, dynamic and electronic aspects in this molecule. Our main objectives are:
1. We will determine the ground state geometry of the haem group and the relative stability of its 15 different isomers.
2. We will analyze the dependence of the ionic and electronic structure on the oxidation and spin state of the iron atom (this dependence is crucial for the biological activity of the haem group).
3. We will analyze the binding of the haem group with 02 and CO, both for the isolated fragment and in the presence of the histidine F8. Besides the specific results expected from the computation described above, the project will provide experience and preliminary results for more ambitious developments. For example, the study of model proteins carrying the haem group are not far from the present computational capabilities.