ROLE OF DNA DEFINITE STRUCTURAL ELEMENTS IN INTERACTION WITH REPAIR ENZYME URACIL-DNA GLYCOSYLASE

Interaction of different oligodeoxyribonucleotides (oligos), their ana logs and oligonucleopeptide with uracil-DNA glycosylase (UDG) from hum an placenta was investigated. It is shown that there is no considerabl e contribution of heterocyclic bases of DNA to UDG-substrate binding b ut the UDG interaction with some DNA phosphate groups is necessary for enzyme-substrate recognition. However the phosphate group adjacent to single dU from the 3'-end in oligo is not involved into the electrost atic contact with UDG. It is found that UDG has the high affinity to i ts reaction product. An oligonucleotide containing a single 2`-deoxy-2 '-aminouridine is a non-hydrolyzable substrate analog for UDG.