National Center for
4M3X: Rb69 Dna Polymerase Ternary Complex With Dt/dg At Position N-5 Of Primer/template Duplex
Mispairs with Watson-Crick base-pair geometry observed in ternary complexes of an RB69 DNA polymerase variant
Protein Sci. (2014) 23 p.508-513
Recent structures of DNA polymerase complexes with dGMPCPP/dT and dCTP/dA mispairs at the insertion site have shown that they adopt Watson-Crick geometry in the presence of Mn(2+) indicating that the tautomeric or ionization state of the base has changed. To see whether the tautomeric or ionization state of base-pair could be affected by its microenvironment, we determined 10 structures of an RB69 DNA polymerase quadruple mutant with dG/dT or dT/dG mispairs at position n-1 to n-5 of the Primer/Template duplex. Different shapes of the mispairs, including Watson-Crick geometry, have been observed, strongly suggesting that the local environment of base-pairs plays an important role in their tautomeric or ionization states.