Theoretical aspects of tetrapyrrole biochemistry

Sammanfattning: Modern theoretical simulations are able to provide significant insight into biochemical problems on a scale which continues to expand. With the aid of computer power and the sophisticated programs of researchers in the field, we have addressed a series of problems related to the so-called tetrapyrrole cofactors found in all living organisms. There have been three major challenges for us, all constituting “classical” problems in bioinorganic chemistry: i) to understand similarities and differences between various tetrapyrroles and why they were chosen by nature for their particular tasks; ii) to understand the way in which the stable, only known bioorganometallic Co-C bond is broken in enzymes; and iii) to understand how heme activates oxygen for binding even though the reaction is spin-forbidden, and how the structural design of heme has facilitated this procedure. The thesis provides some suggestions and hopefully also some answers to all of these three questions.