5'-derivatives of oligonucleotides as primers of DNA polymerization catalyzed by AMV reverse transcriptase and Klenow fragment of DNA polymerase 1.

The Km and Vmax values for d(pT)8 and its derivatives containing various 5'-end groups were estimated in the reaction of polymerization catalyzed with AMV-RT and FK. The change in affinity of modified primers was more pronounced in the case of AMV-RT than in the case of FK. Introducing in d(pT)8 of intercalators such as phenazinium, ethidium and daunomycin residues results in 2.7-, 8.7- and 11-fold increases in the primer affinity to AMV-RT, respectively. However, in the case of hemin and cholesterol derivatives the Km values were 3 and 5 times higher than those for d(pT)8. Compared to d(pT)8, the affinity of FK to all the above analogs was 2.3-3.6 times higher with the exception of cholesterol derivative to which it was 2.4-fold lower. The effect of the 5'-end residues on the Vmax values of d(pT)8 was small and ranged from 44% to 120% of that for d(pT)8. Therefore such reactive derivatives of oligonucleotides can be used as effective primers of AMV-RT and FK. Possible reasons for various effects of the 5'-end residues of the primer on its interaction with FK or AMV-RT in the presence of poly(A) are discussed.