Specific recognition of primer tRNA_3~(Lys) by HIV-1 nucleocapsid protein: involvement of the zinc fingers and the N-terminal basic extension

摘要

Reverse transcription of HIV-1 viral RNA uses human tRNA_3~(Lys) as a primer. We have previously characterised the structural aspects of the tRNA_3~(Lys)/( 12 ― 53 )NCp7 interaction by NMR. In HIV-1 virions, the nucleocapsid protein NCp7 contains two zinc fingers flanked by basic residues. Using NMR, the respective role of the N-terminal residues and the zinc fingers in the interaction with tRNA_3~(Lys) was investigated by studying the tRNA_3~(Lys)/( 1 ― 55 )NCp7 and tRNA_3~(Lys)/Cys~(23)(12 ╚D 53)NCp7 complexes. The N-terminal basic residues do not change the footprint of NC on tRNA_3~(Lys) but strengthen the binding whereas the mutation of the zinc-binding histidine at position 23 that was shown to result in non-infectious particles prevents the interaction with the first bases of the acceptor stem.