Specific recognition of primer tRNA3Lys by HIV-1 nucleocapsid protein:: involvement of the zinc fingers and the N-terminal basic extension

Reverse transcription of HIV-1 viral RNA(3)(Lys) 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 3 studying the tRNA(3)(Lys)/( I - 55)NCp7 and tRNA(3)(Lys)/CYS23( 12 - 53)NCp7 complexes. The N-terminal basic residues do not change the 3 3 Lys 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. (C) 2003 Editions scientifiques et medicales Elsevier SAS and Societe francaise de biochimie et biologie moleculaire. All rights reserved.