Characterization of uracil-DNA glycosylase activity from Trypanosoma cruzi and its stimulation by AP endonuclease.
The intracellular pathogen Trypanosoma cruzi is the etiological agent of Chagas' disease. We have isolated a full-length cDNA encoding uracil-DNA glycosylase (UDGase), a key enzyme involved in DNA repair, from this organism. The deduced protein sequence is highly conserved at the C-terminus of the molecule and shares key residues involved in binding or catalysis with most of the UDGases described so far, while the N-terminal part is highly variable. The gene is single copy and is located on a chromosome of approximately 1.9 Mb. A His-tagged recombinant protein was overexpressed, purified and used to raise polyclonal antibodies. Western blot analysis revealed the existence of a single UDGase species in parasite extracts. Using a specific ethidium bromide fluorescence assay, recombinant T.cruzi UDGase was shown to specifically excise uracil from DNA. The addition of both Leishmania major AP endonuclease and exonuclease III, the major AP endonuclease from Escherichia coli, produces stimulation of UDGase activity. This activation is specific for AP endonuclease and suggests functional communication between the two enzymes.
Instituto de Parasitología y Biomedicina 'López Neyra', Consejo Superior de Investigaciones Científicas, C/ Ventanilla 11, 18001 Granada, Spain.
M E
ME
Fárez-Vidal
C
C
Gallego
L M
LM
Ruiz-Pérez
D
D
González-Pacanowska
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D019757:Carbon-Oxygen Lyases / Q000378:metabolism*; D002874:Chromosome Mapping; D045647:DNA Glycosylases; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004591:Electrophoresis, Polyacrylamide Gel; D029968:Escherichia coli Proteins; D005090:Exodeoxyribonucleases / Q000378:metabolism; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics; D051981:Uracil-DNA Glycosidase
D018076:DNA, Complementary; D029968:Escherichia coli Proteins; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D043223:Deoxyribonuclease IV (Phage T4-Induced); C468972:endonuclease IV, E coli; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase; D019757:Carbon-Oxygen Lyases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase