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"Conversion of phosphoglycolate to phosphate termini on 3' overhangs of DNA double strand breaks by the human tyrosyl-DNA phosphodiesterase hTdp1." |
Inamdar KV, Pouliot JJ, Zhou T, Lees-Miller SP, Rasouli-Nia A, Povirk LF |
Published July 26, 2002 in J Biol Chem volume 277 .
Pubmed ID: 12023295
Abstract:
| Mammalian cells contain potent activity for removal of 3'-phosphoglycolates from single-stranded oligomers and from 3' overhangs of DNA double strand breaks, but no specific enzyme has been implicated in such removal. Fractionated human whole-cell extracts contained an activity, which in the presence of EDTA, catalyzed removal of glycolate from phosphoglycolate at a single-stranded 3' terminus to leave a 3'-phosphate, reminiscent of the human tyrosyl-DNA phosphodiesterase hTdp1. Recombinant hTdp1, as well as Saccharomyces cerevisiae Tdp1, catalyzed similar removal of glycolate, although less efficiently than removal of tyrosine. Moreover, glycolate-removing activity could be immunodepleted from the fractionated extracts by antiserum to hTdp1. When a plasmid containing a double strand break with a 3'-phosphoglycolate on a 3-base 3' overhang was incubated in human cell extracts, phosphoglycolate processing proceeded rapidly for the first few minutes but then slowed dramatically, suggesting that the single-stranded overhangs gradually became sequestered and inaccessible to hTdp1. The results suggest a role for hTdp1 in repair of free radical-mediated DNA double strand breaks bearing terminally blocked 3' overhangs. |
This publication refers to following REPAIRtoire entries:
| Proteins |
Last modification of this entry: Oct. 6, 2010
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