INTERACTION OF PRIMER TRNA(LYS3) WITH THE P51 SUBUNIT OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 REVERSE-TRANSCRIPTASE - A POSSIBLE ROLE IN ENZYME ACTIVATION

In the interaction between HIV-1 RT and tRNA(Lys3) each subunit of the heterodimer interacts with tRNA showing a different affinity: K-d (p6 6) = 23 nM, K-d (p51) = 140 nM, Preincubation of heterodimeric RT with tRNA, at concentrations similar to that of the K-d value for p51, lea ds to an increase of the catalytic activity on poly(il)-oligo(dT). The se results were compared to those using different tRNA analogs: oxidiz ed tRNA, tRNAs lacking one, two or three nucleotides from the 3'-end, or ribo- and deoxyribonucleotides mimicking the anticodon loop sequenc e, In all cases, tRNA analogs were weaker activators of HTV-1 RT than natural tRNA, A possible mechanism of RT p66/p51 activation by tRNA an d its analogs, mediated through the p51 subunit, is discussed.