RECOGNITION OF PRIMERS CONTAINING MISMATCHES AND ABASIC SITES BY KLENOW FRAGMENT OF ESCHERICHIA-COLI DNA-POLYMERASE-I

The K(M) and V(max) values were compared for primers containing mismatches and abasic sites and the control template-complementary ones. It was shown that the efficiency of interaction with Klenow fragment and subsequent extension is determined by the distance between the 3' terminus and the mismatch rather than by the total length of the primer. Klenow fragment practically does not distinguish between primers containing one or two abasic sites and the template-complementary ones. Removal of any base is equivalent to shortening of the primer by one unit and decreases the affinity to the enzyme 1.8-fold. We assumed that at the repair stage DNA polymerases are not involved in repairing abasic sites in the primer strand.