Structural evidence for the rare tautomer hypothesis of spontaneous mutagenesis.
Journal Article (Journal Article)
Even though high-fidelity polymerases copy DNA with remarkable accuracy, some base-pair mismatches are incorporated at low frequency, leading to spontaneous mutagenesis. Using high-resolution X-ray crystallographic analysis of a DNA polymerase that catalyzes replication in crystals, we observe that a C • A mismatch can mimic the shape of cognate base pairs at the site of incorporation. This shape mimicry enables the mismatch to evade the error detection mechanisms of the polymerase, which would normally either prevent mismatch incorporation or promote its nucleolytic excision. Movement of a single proton on one of the mismatched bases alters the hydrogen-bonding pattern such that a base pair forms with an overall shape that is virtually indistinguishable from a canonical, Watson-Crick base pair in double-stranded DNA. These observations provide structural evidence for the rare tautomer hypothesis of spontaneous mutagenesis, a long-standing concept that has been difficult to demonstrate directly.
- Wang, W; Hellinga, HW; Beese, LS
- October 25, 2011
Volume / Issue
- 108 / 43
Start / End Page
- 17644 - 17648
Pubmed Central ID
Electronic International Standard Serial Number (EISSN)
Digital Object Identifier (DOI)
- United States