Biopolymers and cell. 1994. Volume 10. № 1. 76 - 81

S. N. Sukhanov, N. V. Nesterova, M. I. Mendzhul, S. A. Syrchin

TEMPLATE SPECIFICITY AND EXONUCLEASE ACTIVITES OF DNA-POLYMERASES OF CYANOBACTERIA PLECTONEMA BORYANUM

Summary

    Functional characteristics of DNA-dependent DNA-polymerases of cyanobacteria P. boryanum have been studied. DNA-polymerase II (DP-II) have been determined to use activelly the templates with various structures (the most active was the enzyme on DNA P. boryanum and cyanophage LPP-3 which lyse this cyanobacteria); DNA-polymerase I (DP-I) was less active on the most templates tested excluding cyanobacterial DNA. Both enzymes need priming of the synthetic ribonucleic templates and they manifested differ abilities to include each of desoxynucleosidtriphosphates. DP-I and DP-II have 3'—5' exonuclease activity, moreover, DP-II has more potent associated exonuclease. Only DP-I is capable of hydrolysing phosphodiether bonds in directions of 5'— 3'. The conclusion has been made of possible functional role of cyanobacterial DNA-polymerases in vivo: DP-II is the principal cellular replicative enzyme, and DP-I is responsible for realization of reparative processes and close in properties to DNA-polymerase I from E. coli.