Beáta G. Vértessy

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The thymine-uracil exchange constitutes one of the major chemical differences between DNA and RNA. Although these two bases form the same Watson-Crick base pairs with adenine and are equivalent for both information storage and transmission, uracil incorporation in DNA is usually a mistake that needs to be excised. There are two ways for uracil to appear in(More)
The metal ion dependence of the catalytic activity of recombinant Escherichia coli dUTP pyrophosphatase (dUTPase), an essential enzyme preventing incorporation of uracil into DNA, has been investigated by steady-state kinetic, electron paramagnetic resonance, and electron nuclear double resonance methods. Values of k(cat) and k(cat)K(m) were 4.5 +/- 0.1(More)
The molecular mechanism of substrate analogue interaction with Escherichia coli dUTPase was investigated, using the non-hydrolyzable 2'-deoxyuridine 5'-(alpha,beta-imido)triphosphate (alpha,beta-imido-dUTP). Binding of this analogue induces a difference in the far UV circular dichroism (CD) spectrum arguing for a significant change in protein conformation.(More)
The modulatory action of Ca2+-calmodulin on multiple targets is inhibited by trifluoperazine, which competes with target proteins for calmodulin binding. The structure of calmodulin crystallized with two trifluoperazine molecules is determined by X-ray crystallography at 2.74 A resolution. The X-ray data together with the characteristic and distinct signals(More)
The homotrimeric fusion protein nucleocapsid (NC)-dUTPase combines domains that participate in RNA/DNA folding, reverse transcription, and DNA repair in Mason-Pfizer monkey betaretrovirus infected cells. The structural organization of the fusion protein remained obscured by the N- and C-terminal flexible segments of dUTPase and the linker region connecting(More)
dUTPase is responsible for preventive DNA repair via exclusion of uracil. Developmental regulation of the Drosophila enzyme is suggested to be involved in thymine-less apoptosis. Here we show that in addition to conserved dUTPase sequence motifs, the gene of Drosophila enzyme codes for a unique Ala-Pro-rich segment. Kinetic and structural analyses of the(More)
dUTPase is essential to keep uracil out of DNA. Crystal structures of substrate (dUTP and alpha,beta-imino-dUTP) and product complexes of wild type and mutant dUTPases were determined to reveal how an enzyme responsible for DNA integrity functions. A kinetic analysis of wild type and mutant dUTPases was performed to obtain relevant mechanistic information(More)
Proteins are translated in the cytoplasm, but many need to access the nucleus to perform their functions. Understanding how these nuclear proteins are transported through the nuclear envelope and how the import processes are regulated is therefore an important aspect of understanding cell function. Structural biology has played a key role in understanding(More)
Simultaneous binding of two sequential glycolytic enzymes, phosphofructokinase and aldolase, to a microtubular network was investigated. The binding of the phosphofructokinase to microtubules and its bundling activity has been previously characterized (Lehotzky, A., Telegdi, M., Liliom, K., and Ovádi, J. (1993) J. Biol. Chem. 268, 10888-10894). Aldolase(More)
dUTPase prevents uracil incorporation into DNA by strict regulation of the cellular dUTP:dTTP ratio. Lack of the enzyme initiates thymineless cell death, prompting studies on enzyme regulation. We investigated expression pattern and localization of Drosophila dUTPase. Similarly to human, two isoforms of the fly enzyme were identified at both mRNA and(More)