STRUCTURAL CONSTRAINTS IN THE HIV-1 REVERSE TRANCRIPTASE-PRIMER TEMPLATE COMPLEX FOR THE INITIATION OF DNA-SYNTHESIS FROM PRIMER TRNA(LYS3)/

The topography and functional implications of the complex formed in vi tro between human immunodeficiency virus type 1 (HIV-1) reverse transc riptase (RT) and its primer tRNA(Lys3) were studied in this work. On t he basis of previous results showing the high affinity both of the nat ive primer, tRNA(Lys3), as well as that of mismatched short oligonucle otide primers for HIV-1 RT, we synthesized chimeric primers containing tRNA(Lys3) linked to U and T residues of different lengths. We found that the affinity of the oligonucleotide primers for HIV-1 RT is drama tically increased when linked to primer tRNA. Our results also show th at in the tRNA RT complex, before annealing tRNA(Lys3) to the retrovir al RNA genome, the 3'-terminal nucleotide of tRNA(Lys3) is positioned at a distance of one nucleotide unit away from the template in the act ive polymerization site of the enzyme.