title: Secondary structure of the HIV reverse transcription initiation complex by NMR.
abstract: Initiation of reverse transcription of genomic RNA is a key early step in replication of the human immunodeficiency virus (HIV) upon infection of a host cell. Viral reverse transcriptase initiates from a specific RNA-RNA complex formed between a host transfer RNA (tRNA(Lys)(3)) and a region at the 5' end of genomic RNA; the 3' end of the tRNA acts as a primer for reverse transcription of genomic RNA. We report here the secondary structure of the HIV genomic RNA-human tRNA(Lys)(3) initiation complex using heteronuclear nuclear magnetic resonance methods. We show that both RNAs undergo large-scale conformational changes upon complex formation. Formation of the 18-bp primer helix with the 3' end of tRNA(Lys)(3) drives large conformational rearrangements of the tRNA at the 5' end while maintaining the anticodon loop for potential loop-loop interactions. HIV RNA forms an intramolecular helix adjacent to the intermolecular primer helix. This helix, which must be broken by reverse transcription, likely acts as a kinetic block to reverse transcription.
authors.affiliation: Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305-5126, USA. epuglisi@stanford.edu
authors.forename: Elisabetta Viani
authors.initials: EV
authors.lastname: Puglisi
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Puglisi
mesh_terms: D001483:Base Sequence; D016679:Genome, Viral; D006678:HIV / Q000737:chemistry / Q000235:genetics*; D015497:HIV-1 / Q000737:chemistry / Q000235:genetics; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012357:RNA, Transfer, Lys / Q000737:chemistry* / Q000235:genetics; D012367:RNA, Viral / Q000737:chemistry* / Q000235:genetics; D048348:Reverse Transcription / Q000235:genetics*
chemical_list: D012357:RNA, Transfer, Lys; D012367:RNA, Viral