NMR Investigation of DNA Primer-Template Models: Guanine Templates Are Less Prone to Strand Slippage upon Misincorporation

摘要

Misaligned structures can result fromstrand slippage duringDNAreplication and, if not repaired,nwould lead to mutations. Previously, we showed that strand slippage can occur upon misincorporation of andNTP opposite thymine and cytosine templates, resulting in a misaligned structure with a T- or C-bulge. Thenformation propensity for misaligned structures was found to depend on the type of terminal base pair. In thisnstudy, we performed NMR investigations on primer-template models containing a guanine template. Ournresults reveal guanine templates are less prone to strand slippage than pyrimidine templates. Misalignmentnwas found to occur only in 50n-CG templates with a downstream purine. In addition to the significance ofnterminal base pair and upstream nucleotide, the present study reveals the importance of the templating basenand its downstream nucleotide, which also determine the propensity of strand slippage in primer-templates.