1 Department of Molecular Biology and Genetics - Genome stability and technology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University2 Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), University of Rome3 Institute of Translational Pharmacology, National Research Council, CNR4 Department of Molecular Biology and Genetics - Genome stability and technology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
A human/plasmodial hybrid enzyme, generated by swapping the human topoisomerase IB linker domain with the corresponding domain of the Plasmodium falciparum enzyme, has been produced and characterized. The hybrid enzyme displays a relaxation activity comparable to the human enzyme, but it is characterized by a much faster religation rate. The hybrid enzyme is also camptothecin resistant. A 3D structure of the hybrid enzyme has been built and its structural-dynamical properties have been analyzed by molecular dynamics simulation. The analysis indicates that the swapped plasmodial linker samples a conformational space much larger than the corresponding domain in the human enzyme. The large linker conformational variability is then linked to important functional properties such as an increased religation rate and a low drug reactivity, demonstrating that the linker domain has a crucial role in the modulation of the topoisomerase IB activity.