Interaction of primer tRNALys3 with the p51 subunit of human immunodeficiency virus type 1 reverse transcriptase: a possible role in enzyme activation

Abstract

In the interaction between HIV-1 RT and tRNA Lys3 each subunit of the heterodimer interacts with tRNA showing a different affinity: K d (p66) = 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, leads to an increase of the catalytic activity on poly(A)-oligo(dT). These results were compared to those using different tRNA analogs: oxidized tRNA, lacking one, two or three nucleotides from the 3′-end, or ribo- and deoxyribonucleotides mimicking the anticodon loop sequence. In all cases, tRNA analogs were weaker activators of HIV-1 RT than natural tRNA. A possible mechanism of RT p66/p51 activation by tRNA and its analogs, mediated through the p51 subunit, is discussed.