title: No tRNA3Lys unwinding in a complex with HIV NCp7.
abstract: The nucleocapsid protein NCp7 of the human immunodeficiency virus (HIV) type 1 is important for the annealing of HIV RNA and tRNA3Lys, the tRNA acting as a primer during reverse transcription of HIV RNA. A wild type NCp7 and a Cys23 mutant having a disrupted zinc finger were analyzed with far UV circular dichroism (CD). CD data analysis revealed that NCp7 has a high content of extended structures in aqueous buffer, decreasing in Cys23 NCp7 and in NCp7 in the absence of zinc. An increase in beta-turn structures is observed in NCp7 bound to tRNA3Lys. Furthermore, CD data shows that Cys23 NCp7 binds tRNA3Lys. The CD spectrum of tRNA3Lys is typical of an A-form helix and retains this structure after binding of NCp7, which demonstrates that NCp7 does not induce tRNA3Lys unwinding. CD spectra of tRNA3Lys were measured from 5 to 80 degrees C to observe CD changes resulting from tRNA3Lys melting. Molecular modeling of the complex identifies two potential tRNA anticodon binding sites in the NCp7 N-terminal region and first zinc finger. In this model, both binding sites can interact with 12 nucleotides in the anticodon domain without requiring a base specificity.
authors.affiliation: Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Biologie Structurale et Microbiologie, CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: C J
authors.initials: CJ
authors.lastname: Gregoire
authors.forename: D
authors.initials: D
authors.lastname: Gautheret
authors.forename: E P
authors.initials: EP
authors.lastname: Loret
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002213:Capsid / Q000737:chemistry* / Q000378:metabolism*; D036022:Capsid Proteins; D002942:Circular Dichroism; D015683:Gene Products, gag / Q000737:chemistry* / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D017433:Protein Structure, Secondary; D013056:Spectrophotometry, Ultraviolet; D014764:Viral Proteins; D016335:Zinc Fingers; D054301:gag Gene Products, Human Immunodeficiency Virus
chemical_list: D036022:Capsid Proteins; D015683:Gene Products, gag; C071884:NCP7 protein, Human immunodeficiency virus 1; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus