The single-finger nucleocapsid protein of Moloney murine leukemia virus binds and destabilizes the TAR sequences of HIV-1 but does not promote efficiently their annealing
Fiche publication
Date publication
décembre 2007
Auteurs
Membres identifiés du Cancéropôle Est :
Pr MELY Yves
Tous les auteurs :
Egele C, Piemont E, Didier P, Ficheux D, Roques B, Darlix JL, de Rocquigny H, Mely Y
Lien Pubmed
Résumé
The retroviral nucleocapsid proteins (NCs) are small proteins with either one or two conserved zinc fingers flanked by basic domains. NCs play key roles during reverse transcription by chaperoning the obligatory strand transfers. In HIV-1, the first DNA strand transfer relies on the NCp7-promoted destabilization and subsequent annealing of the transactivation response element, TAR with its complementary cTAR sequence. NCp7 chaperone activity relies mainly on its two folded fingers. Since NCs with a unique zinc finger are encoded by gammaretroviruses such as the canonical Moloney murine leukemia virus (MoMuLV), our objective was to characterize, by fluorescence techniques, the binding and chaperone activities of the NCp10 protein of MoMuLV to the TAR sequences of HIV-1. The unique finger and the flanking 12-25 and 40-48 domains of NCp10 were found to bind and destabilize cTAR stem-loop almost as efficiently as the homologous NCp7 protein. The flanking domains were essential for properly positioning the finger and, notably, the Trp35 residue onto cTAR. Thus, the binding and destabilization determinants scattered on the two NCp7 fingers are encoded-by the unique finger of NCp10 and its flanking domains. NCp10 also activates the cTAR/TAR annealing reaction, but less efficiently than NCp7, suggesting that the two NCp7 fingers promote in concert the rate-limiting nucleation of the duplex. Due to its ability to mimic NCp7, the simple structure of NCp10 might be useful to design peptidomimetics aimed at inhibiting HIV replication.
Référence
Biochemistry. 2007 Dec 18;46(50):14650-62