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Mechanism of nucleotide incorporation opposite a thymine-thymine dimer by yeast DNA polymerase η
Journal article   Open access   Peer reviewed

Mechanism of nucleotide incorporation opposite a thymine-thymine dimer by yeast DNA polymerase η

M. Todd Washington, Louise Prakash and Satya Prakash
Proceedings of the National Academy of Sciences - PNAS, Vol.100(21), pp.12093-12098
10/14/2003
DOI: 10.1073/pnas.2134223100
PMCID: PMC218718
PMID: 14527996
url
https://doi.org/10.1073/pnas.2134223100View
Published (Version of record) Open Access

Abstract

DNA polymerase η (Polη) has the unique ability to replicate through UV-light-induced cyclobutane pyrimidine dimers. Here we use pre-steady-state kinetic analyses to examine the mechanism of nucleotide incorporation opposite a cis - syn thymine-thymine (TT) dimer and an identical nondamaged sequence by yeast Polη. Polη displayed “burst” kinetics for nucleotide incorporation opposite both the damaged and nondamaged templates. Although a slight decrease occurred in the affinity ( K d ) of nucleotide binding opposite the TT dimer relative to the nondamaged template, the rate ( k pol ) of nucleotide incorporation was the same whether the template was damaged or nondamaged. These results strongly support a mechanism in which the nucleotide is directly inserted opposite the TT dimer by using its intrinsic base-pairing ability without any hindrance from the distorted geometry of the lesion.
Biological Sciences

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