Final Report Summary - ALPROS (Artificial Life-like Processive Systems)
Processive catalysts are found in Nature and are involved in important biochemical processes that have to be carried out with high precision. They are composed of ring-shaped proteins that move along biopolymers while performing a catalytic reaction, e.g. the duplication or cleavage of DNA. We have been able to synthesize a biohybrid catalytic system on the basis of a C-shaped protein that is involved in DNA replication. This protein was modified with 3 manganese porphyrin molecules and was used as a catalyst for the oxidative cleavage of DNA chains at adenine-adenine-adenine (AAA) sites. It was shown by extensive statistical analysis that the cleavage reaction proceeds unidirectional in a stepwise processive way. This is the first example of such a synthetic catalytic system to date. The information and knowledge obtained from this research was used to develop a synthetic machine composed of a cage compound with a porphyrin roof that can be threaded and move on a polymer with carbon-carbon double bonds. By the catalytic action of the porphyrin complex the polymer double bonds are converted into epoxide functions, which can be seen as writing on a thread. A double cage catalyst in which information from one cage to the other cage can be transferred by changes in shape of the compound (allosteric interactions) has also been synthesized as part of this project. Furthermore, a porphyrin cage compound with a threaded ring has been prepared. It can shuttle between two states (zero and one) in which the ring has different positions with respect to the porphyrin molecule. This ring containing cage compound will be used in the future as the tape head of a molecular Turing Machine, i.e. a machine that can write and read information on a polymer thread.