Heterogeneous structures formed by conserved RNA sequences within the HIV reverse transcription initiation site.
Reverse transcription is a key process in the early steps of HIV infection. This process initiates within a specific complex formed by the 5' UTR of the HIV genomic RNA (vRNA) and a host primer tRNALys3Using nuclear magnetic resonance (NMR) spectroscopy and single-molecule fluorescence spectroscopy, we detect two distinct conformers adopted by the tRNA/vRNA initiation complex. We directly show that an interaction between the conserved 8-nucleotide viral RNA primer activation signal (PAS) and the primer tRNA occurs in one of these conformers. This intermolecular PAS interaction likely induces strain on a vRNA intramolecular helix, which must be broken for reverse transcription to initiate. We propose a mechanism by which this vRNA/tRNA conformer relieves the kinetic block formed by the vRNA intramolecular helix to initiate reverse transcription.
Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA.|Biophysics Program, Stanford University School of Medicine, Stanford, California 94305-5126, USA.
Aaron
A
Coey
Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA.|Biophysics Program, Stanford University School of Medicine, Stanford, California 94305-5126, USA.
Kevin
K
Larsen
Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA.
Joseph D
JD
Puglisi
Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305-5126, USA.
Elisabetta
E
Viani Puglisi
D020121:5' Untranslated Regions; D031541:Fluorescence Resonance Energy Transfer; D006678:HIV / Q000235:genetics*; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000737:chemistry* / Q000235:genetics; D048348:Reverse Transcription; D024363:Transcription Initiation Site
D020121:5' Untranslated Regions; D012367:RNA, Viral
HIV RNA structure; NMR spectroscopy; reverse transcription; single-molecule FRET