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"Mismatch extension ability of yeast and human DNA polymerase eta." |
Washington MT, Johnson RE, Prakash S, Prakash L |
Published Feb. 19, 2001 in J Biol Chem volume 276 .
Pubmed ID: 11054429
Abstract:
| DNA polymerase eta (Poleta) functions in error-free replication of UV-damaged DNA, and in vitro it efficiently bypasses a cis-syn T-T dimer by incorporating two adenines opposite the lesion. Steady state kinetic studies have shown that both yeast and human Poleta are low-fidelity enzymes, and they misincorporate nucleotides with a frequency of 10(-2)-10(-3) on both undamaged and T-T dimer-containing DNA templates. To better understand the role of Poleta in error-free translesion DNA synthesis, here we examine the ability of Poleta to extend from base mismatches. We find that both yeast and human Poleta extend from mismatched base pairs with a frequency of approximately 10(-3) relative to matched base pairs. In the absence of efficient extension of mismatched primer termini, the ensuing dissociation of Poleta from DNA may favor the excision of mismatched nucleotides by a proofreading exonuclease. Thus, we expect DNA synthesis by Poleta to be more accurate than that predicted from the fidelity of nucleotide incorporation alone. |
This publication refers to following REPAIRtoire entries:
| Proteins |
Last modification of this entry: Oct. 6, 2010
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