Journal: PLoS ONE
Article Title: Expression and the Peculiar Enzymatic Behavior of the Trypanosoma cruzi NTH1 DNA Glycosylase
Figure Lengend Snippet: TcNTH1 does not present mono nor bifunctional DNA glycosylase activities but an AP endonuclease activity. A, B and C: A [γ-32P]ATP labeled 32 mer oligonucleotide containing a thymine glycol residue at position 18 incubated without enzyme (negative control, lane 1) or with E . coli Endo III (bacterial NTH1, positive control, lane 2). A: Lanes 3 and 4, same oligo incubated with native TcNTH1 purified from transformed bacteria or purified from transfected epimastigotes, respectively. B: Lane 3 same oligo co-incubated with native TcNTH1 purified from transformed bacteria and with native TcAP1 endonuclease. Lanes 4 and 5 same oligo incubated with native TcNTH1 purified from transformed bacteria or incubated with native TcAP1, respectively. C: Lanes 3 and 4 same oligo incubated with epimastigote or trypomastigote homogenates, respectively. D: A [γ- 32 P]ATP labeled 25-mer oligonucleotide with an AP site at position 8, was incubated with E . coli Endo III (AP lyase, positive control, lane 3), with native TcNTH1 purified from transformed bacteria (lane 4) and with native TcNTH1 purified from transfected epimastigotes (lane 5). Lane 1 same oligo incubated without enzyme (negative control). Lanes 2 and 6 same oligo incubated with E . coli Exo III (canonic AP endonuclease, positive control) or with TcAP1 AP endonuclease, respectively. A densitometric analysis of bands was performed using the Quantity One version 4.6.3 program (Bio Rad). S: substrate, P: product.
Article Snippet: Afterwards, 1μg of TcNTH1 native recombinant protein was incubated with 2 pg of the oligo substrate in Endonuclease III (Endo III) buffer solution (New England Biolabs, 20 mM Tris-HCl pH 8.0, 1 mM EDTA, 1 mM DTT) for 1 h at 37°C.
Techniques: Activity Assay, Labeling, Incubation, Negative Control, Positive Control, Purification, Transformation Assay, Transfection