Quesada-Soriano Indalecio, Musso-Buendia Juan Alexander, Tellez-Sanz Ramiro, Ruíz-Pérez Luis Miguel, Barón Carmen, González-Pacanowska Dolores, García-Fuentes Luis
Dipartimento de Química Física, Bioquímica y Q. Inorgánica, Facultad de Ciencias Experimentales, Universidad de Almería, La Cañada de San Urbano, 04120 Almería, Spain.
Biochim Biophys Acta. 2007 Jul;1774(7):936-45. doi: 10.1016/j.bbapap.2007.04.013. Epub 2007 May 5.
Deoxyuridine triphosphate nucleotidohydrolase (dUTPase), a ubiquitous enzyme preventing a deleterious incorporation of uracil into DNA, has been thought of as a novel target for anticancer and antiviral drug design. The interaction of Plasmodium falciparum dUTPase (PfdUTPase) with deoxyuridine derivatives (dU, dUMP, dUDP and dUpNHpp) has been studied thermodynamically by both isothermal titration and differential scanning calorimetry. ITC shows no cooperativity for the binding of these derivatives. Dependencies in the binding thermodynamic parameters (enthalpy, entropy and Gibbs energy changes) with the number of phosphate groups in the nucleotide are obtained, and from the heat capacity changes no significant conformational changes upon binding are inferred. DSC shows PfdUTPase trimer is very stable but denatures irreversibly, with a more complex denaturation profile than other homologous trimeric dUTPases. The presence of magnesium ions does not influence the denaturation profile, while the presence of deoxyuridine derivatives increases the stability. The increase depends upon nucleotide concentration and type, with dUDP having the greater effect.
