α,β-Difluoromethylene Deoxynucleoside 5′-Triphosphates: A Convenient Synthesis of Useful Probes for DNA Polymerase β Structure and Function

α,β-Difluoromethylene deoxynucleoside 5′-triphosphates (dNTPs, N = A or C) are advantageously obtained via phosphorylation of corresponding dNDP analogues using catalytic ATP, PEP, nucleoside diphosphate kinase, and pyruvate kinase. DNA pol β K_d values for the α,β-CF₂ and unmodified dNTPs, α,β-NH dUTP, and the α,β-CH₂ analogues of dATP and dGTP are discussed in relation to the conformations of α,β-CF₂ dTTP versus α,β-NH dUTP bound into the enzyme active site.