THE AFFINITY OF THE KLENOW FRAGMENT OF ESCHERICHIA-COLI DNA-POLYMERASE-1 TO PRIMERS CONTAINING BASES NONCOMPLEMENTARY TO THE TEMPLATE AND HAIRPIN-LIKE ELEMENTS

The K(max) and V(max) values for a set of primers: d(pT)n (pC) (pT)m ( n = 3-9, m = 0-7) and d(pT)4 (pCpG)k (pT)4 (k = 1-5) have been estimat ed. Poly(dA) was used as a template. The number of complementary bases from the 3' end to a noncomplementary ones was shown to determine the efficiency of interaction of d(pT)n (pC) (pT)m, with the Klenow fragm ent. Oligonucleotides d(pT)4 (pCpG)k (pT)4, in solution forming duplex es containing hairpin-like elements, show a higher affinity to the enz yme than control d(pT)4, d(pT)8 and d(pT)n (pC) (pT)m primers. For exa mple, the K(m) value (1.1 nM) for d(pT)4 (pCpG)5 (pT)4 is about 14,000 and 200 times lower than those for d(pT)4 and d(pT)8, respectively. P ossible reasons for such an abnormally high affinity of the above prim ers are discussed.