Margarita Sandigursky

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Uracil-DNA glycosylase (UDG) is an essential enzyme for maintaining genomic integrity. Here we describe a UDG from the extreme thermophile Archaeoglobus fulgidus. The enzyme is a member of a new class of enzymes found in prokaryotes that is distinct from the UDG enzyme found in Escherichia coli, eukaryotes, and DNA-containing viruses. The A. fulgidus UDG is(More)
Uracil-DNA glycosylase (UDG) is a ubiquitous enzyme found in eukaryotes and prokaryotes [1][2][3]. This enzyme removes uracil bases that are present in DNA as a result of either deamination of cytosine or misincorporation of dUMP instead of dTMP [4] [5], and it is the primary activity in the DNA base excision repair pathway. Although UDG activities have(More)
DNA deoxyribophosphodiesterase (dRpase) of E. coli catalyzes the release of deoxyribose-phosphate moieties following the cleavage of DNA at an apurinic/apyrimidinic (AP) site by either an AP endonuclease or AP lyase. Exonuclease I is a single-strand specific DNA nuclease which affects the expression of recombination and repair pathways in E. coli. We show(More)
It was demonstrated previously that a deoxyribophosphodiesterase (dRpase) activity is associated with the DNA repair enzyme exonuclease I, and that this activity is stimulated by the addition of the E. coli single-stranded DNA-binding protein (Ssb). This activity catalyzes the release of deoxyribose-phosphate groups at apurinic/apyrimidinic (AP) sites in(More)
The extremely radiation resistant bacterium, Deinococcus radiodurans, contains a spectrum of genes that encode for multiple activities that repair DNA damage. We have cloned and expressed the product of three predicted uracil-DNA glycosylases to determine their biochemical function. DR0689 is a homologue of the Escherichia coli uracil-DNA glycosylase, the(More)
Two enzymes of base excision repair (BER), uracil DNA glycosylase (UDG) and DNA polymerase beta (beta pol), from HeLa cells co-eluted from Superose 12 FPLC columns. The UDG was completely displaced from 150-180-kDa fractions to 30- 70-kDa fractions by brief treatment with 0.5 N NaCl, pH 3.0, as expected when protein-protein associations are disrupted, but(More)
The DNA base excision repair pathway is responsible for removal of oxidative and endogenous DNA base damage in both prokaryotes and eukaryotes. This pathway involves formation of an apurinic/apyrimidinic (AP) site in the DNA, which is further processed to restore the integrity of the DNA. In Escherichia coli it has been suggested that the major mode of(More)
The interaction of human heat shock protein 70 (HSP70) with human apurinic/apyrimidinic endonuclease (HAP1) was demonstrated by coimmunoprecipitation. A combination of HSP70 and HAP1 also caused a shift in the electrophoretic mobility of a DNA fragment containing an apurinic/apyrimidinic site. The functional consequence of the HSP70/HAP1 interaction was a(More)
The Drosophila ribosomal protein S3 has been previously demonstrated to cleave DNA containing 8-oxoguanine residues and has also been found to contain an associated apurinic/apyrimidinic (AP) lyase activity that cleaves phosphodiester bonds via a beta, delta-elimination reaction. The activity of this protein on DNA substrates containing incised AP sites was(More)
We previously demonstrated the stimulation of human apurinic/apyrimidinic endonuclease 1 (HAP1) by heat shock protein 70 (HSP70). In this work, we further defined the functional interaction between these proteins. Digestion of HSP70 by trypsin released 48 and 43 kDa amino terminal fragments that retained the ability to stimulate HAP1. In agreement with this(More)