title: Plasmodium falciparum dUTPase: studies on protein stability and binding of deoxyuridine derivatives.
abstract: 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.
authors.affiliation: Dipartimento de Química Física, Bioquímica y Q. Inorgánica, Facultad de Ciencias Experimentales, Universidad de Almería, La Cañada de San Urbano, 04120 Almería, Spain.
authors.forename: Indalecio
authors.initials: I
authors.lastname: Quesada-Soriano
authors.forename: Juan Alexander
authors.initials: JA
authors.lastname: Musso-Buendia
authors.forename: Ramiro
authors.initials: R
authors.lastname: Tellez-Sanz
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Ruíz-Pérez
authors.forename: Carmen
authors.initials: C
authors.lastname: Barón
authors.forename: Dolores
authors.initials: D
authors.lastname: González-Pacanowska
authors.forename: Luis
authors.initials: L
authors.lastname: García-Fuentes
mesh_terms: D000818:Animals; D001703:Biophysics / Q000379:methods; D002151:Calorimetry; D002152:Calorimetry, Differential Scanning; D003857:Deoxyuridine / Q000737:chemistry*; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry; D008956:Models, Chemical; D009711:Nucleotides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D010963:Plasmodium falciparum / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry; D011755:Pyrophosphatases / Q000737:chemistry*; D013696:Temperature
chemical_list: D009711:Nucleotides; D010710:Phosphates; D011506:Proteins; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase; D008274:Magnesium; D003857:Deoxyuridine