title: Replacement of the human topoisomerase linker domain with the plasmodial counterpart renders the enzyme camptothecin resistant.
abstract: 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.
authors.affiliation: Department of Biology and Interuniversity Consortium, National Institute Biostructure and Biosystem, University of Rome Tor Vergata, Rome, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Arnò
authors.forename: Ilda
authors.initials: I
authors.lastname: D'Annessa
authors.forename: Cinzia
authors.initials: C
authors.lastname: Tesauro
authors.forename: Laura
authors.initials: L
authors.lastname: Zuccaro
authors.forename: Alessio
authors.initials: A
authors.lastname: Ottaviani
authors.forename: Birgitta
authors.initials: B
authors.lastname: Knudsen
authors.forename: Paola
authors.initials: P
authors.lastname: Fiorani
authors.forename: Alessandro
authors.initials: A
authors.lastname: Desideri
mesh_terms: D001665:Binding Sites / Q000235:genetics; D055162:Biocatalysis / Q000187:drug effects; D002166:Camptothecin / Q000494:pharmacology*; D004264:DNA Topoisomerases, Type I / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004278:DNA, Superhelical / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D010963:Plasmodium falciparum / Q000201:enzymology / Q000235:genetics; D025341:Principal Component Analysis; D015202:Protein Engineering / Q000379:methods; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013379:Substrate Specificity; D059004:Topoisomerase I Inhibitors / Q000494:pharmacology
chemical_list: D004278:DNA, Superhelical; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D059004:Topoisomerase I Inhibitors; D004264:DNA Topoisomerases, Type I; C528909:TOP1 protein, human; D002166:Camptothecin