A diadenosine 5',5''-P1P4 tetraphosphate (Ap4A) hydrolase from Arabidopsis thaliana that is activated preferentially by Mn2+ ions.

Blanka Szurmak; Aleksandra Wysłouch-Cieszyńska; Małgorzata Wszelaka-Rylik; Wojciech Bal; Marta Dobrzańska

doi:10.18388/abp.2008_3173

A diadenosine 5',5''-P1P4 tetraphosphate (Ap4A) hydrolase from Arabidopsis thaliana that is activated preferentially by Mn2+ ions.

Blanka Szurmak Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland.;
Aleksandra Wysłouch-Cieszyńska
Małgorzata Wszelaka-Rylik
Wojciech Bal
Marta Dobrzańska

DOI: https://doi.org/10.18388/abp.2008_3173

Abstract

Asymmetrical diadenosine 5',5''-P(1)P(4) tetraphosphate (Ap(4)A) hydrolases are key enzymes controlling the in vivo concentration of Ap(4)A--an important signaling molecule involved in regulation of DNA replication and repair, signaling in stress response and apoptosis. Sequence homologies indicate that the genome of the model plant Arabidopsis thaliana contains at least three open reading frames encoding presumptive Ap(4)A hydrolases: At1g30110, At3g10620, and At5g06340. In this work we present efficient overexpression and detailed biochemical characteristics of the AtNUDX25 protein encoded by the At1g30110 gene. Aided by the determination of the binding constants of Mn(Ap(4)A) and Mg(Ap(4)A) complexes using isothermal titration calorimetry (ITC) we show that AtNUDX25 preferentially hydrolyzes Ap(4)A in the form of a Mn(2+) complex.

Published

2008-03-13

Issue

Vol. 55 No. 1 (2008)

Section

Articles

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