Thermostable DNA polymerase from Thermus thermophilus B35: Influence of divalent metal ions on the interaction with deoxynucleoside triphosphates

The interaction of DNA polymerase from Thermus thermophilus B35 (Tte-pol) w ith deoxynucleoside triphosphates in the presence of different divalent met al ions has been studied. DNA synthesis and competitive inhibition of the p olymerase reaction by non-complementary dNTPs are described with correspond ing kinetic schemes. The co-factor properties of some metals (Mg2+, Mn2+, C o2+, Ni2+, Cu2+, Ca2+, Cd2+, and Zn2+) were investigated, and their activat ing concentration ranges were determined. It was found that k(cat) values a re significantly decreased and K-m values slowly decrease when Mn2+ displac es Mg2+. The value of K-d for DNA template-primer is Me2+-independent, wher eas K-d values for non-complementary dNTPs decrease in the presence of Mn2. Tte-pol processivity but not DNA synthesis efficiency is Me2+-type indepe ndent.