The repair patch of E. coli (A)BC excinuclease. |
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| Authors: | Sibghat-Ullah A Sancar J E Hearst |
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| Affiliation: | Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599. |
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| Abstract: | The size of repair patch made by E. coli DNA polymerase I (Poll) following the removal of a thymine-psoralen monoadduct by E. coli (A)BC excinuclease was determined by using an M13mp19 DNA with a single psoralen monoadduct at the polylinker region. Incubation of this substrate with (A)BC excinuclease, Poll and a combination of 3 dnTP plus 1 dNTP(alpha S) for each nucleotide, and DNA ligase resulted in a repair patch with phosphorothioate linkages. The preferential hydrolysis of phosphorothioate bonds by heating in iodoethanol revealed a patch size--with minimal nick translation--equal in length to the 12 nucleotide gap generated by this excision nuclease. |
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