Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase.

Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Research Abstract Details 

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Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Abstract Text:

Ramiro ,Zeyad Yassin,Victor Bernier-Villamor,Emilia ,Juan Alexander Musso-Buendia,Carmen ,Luis Miguel ,Dolores ,Luis ,

dUTPase (deoxyuridine 5'-triphosphate nucleotide hydrolase) is an enzyme responsible for maintaining low levels of intracellular dUTP and thus prevents uracil incorporation into DNA by DNA polymerases during replication and repair processes. The thermodynamics of binding for both dUTP and dUMP (deoxyuridine 5'-monophosphate) to the D80A mutant form of Trypanosoma cruzi dUTPase have been investigated by fluorescence spectroscopy and high-sensitivity isothermal titration calorimetry. In the presence of magnesium, approximately a 30-fold decrease in the value of the k(cat) and a 15-fold increase in the K(m) for dUTP hydrolysis was calculated while a 5-fold decrease was observed in the affinity for dUMP. In the absence of magnesium, the affinity for dUTP binding was similar for both enzymes while that for dUMP was lowered 3-fold as a consequence of the mutation. Calorimetric titrations in several buffers with different ionization heats rendered similar proton exchanges during the binding of dUMP. Thus, apparently the side chain of Asp 80 does not seem to vary its protonation state during the binding process. The enthalpy change values for the D80A mutant hardly change with temperature and, in addition, were Mg(2+) independent. We conclude that the D80A mutation induces only a slight conformational change in the active site yet results in a significant alteration of nucleotide binding and modifies the ability of the enzyme to discriminate between dUTP and dUMP when magnesium is present.

Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Publishing Authors By Initials

R ,Z Yassin,V Bernier-Villamor,E ,JA Musso-Buendia,C ,LM ,D ,L ,

For similar animals: invertebrates: protozoa: sarcomastigophora: mastigophora: zoomastigophora: kinetoplastida: trypanosomatina: trypanosoma: trypanosoma cruzi research abstracts see: animals: invertebrates: protozoa: sarcomastigophora: mastigophora: zoomastigophora: kinetoplastida: trypanosomatina: trypanosoma: trypanosoma cruzi research

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Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Journal Published:

PUBLICATION TYPE: Research Support, Non-U.S. Gov

Journal: Biochimie

VOLUME: 89

Page Numbers: 972-80

Journal Abbreviation: Biochimie

ISSN: 0300-9084

DAY: 19

MONTH: 03

YEAR: 2007

Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Information

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LANGUAGE: eng

NlmUniqueID: 1264604

Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Keywords Mesh Terms:

KEYWORDS: Trypanosoma cruzi

MESH TERMS: enzymology

Chemical & Substance for Abstract: Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase. Information

Substance Name: dUTP pyrophosphatase

Registry Number: EC 3.6.1.23

Grant and Affiliation Information for Effect of an Asp80Ala substitution on the binding of dUTP and dUMP to Trypanosoma cruzi dUTPase.

AFFILIATION: Departamento de Química Física, Bioquímica y Química Inorgánica, Facultad de Ciencias Experimentales, Universidad de Almería, La Cañada de San Urbano, 04120 Almería, Spain.

Country: France

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MEDLINETA: Biochimie

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