Skip to main content
Journal cover image

Resolving fast and slow motions in the internal loop containing stem-loop 1 of HIV-1 that are modulated by Mg2+ binding: role in the kissing-duplex structural transition.

Publication ,  Journal Article
Sun, X; Zhang, Q; Al-Hashimi, HM
Published in: Nucleic Acids Res
2007

Stem loop 1 (SL1) is a highly conserved hairpin in the 5'-leader of the human immunodeficiency virus type I that forms a metastable kissing dimer that is converted during viral maturation into a stable duplex with the aid of the nucleocapsid (NC) protein. SL1 contains a highly conserved internal loop that promotes the kissing-duplex transition by a mechanism that remains poorly understood. Using NMR, we characterized internal motions induced by the internal loop in an SL1 monomer that may promote the kissing-duplex transition. This includes micro-to-millisecond secondary structural transitions that cause partial melting of three base-pairs above the internal loop making them key nucleation sites for exchanging strands and nanosecond rigid-body stem motions that can help bring strands into spatial register. We show that while Mg2+ binds to the internal loop and arrests these internal motions, it preserves and/or activates local mobility at internal loop residues G272 and G273 which are implicated in NC binding. By stabilizing SL1 without compromising the accessibility of G272 and G273 for NC binding, Mg2+ may increase the dependence of the kissing-duplex transition on NC binding thus preventing spontaneous transitions from taking place and ensuring that viral RNA and protein maturation occur in concert.

Duke Scholars

Published In

Nucleic Acids Res

DOI

EISSN

1362-4962

Publication Date

2007

Volume

35

Issue

5

Start / End Page

1698 / 1713

Location

England

Related Subject Headings

  • RNA, Viral
  • Nucleic Acid Conformation
  • Nuclear Magnetic Resonance, Biomolecular
  • Motion
  • Molecular Sequence Data
  • Models, Molecular
  • Magnesium
  • Kinetics
  • HIV-1
  • Dimerization
 

Citation

Journal cover image

Published In

Nucleic Acids Res

DOI

EISSN

1362-4962

Publication Date

2007

Volume

35

Issue

5

Start / End Page

1698 / 1713

Location

England

Related Subject Headings

  • RNA, Viral
  • Nucleic Acid Conformation
  • Nuclear Magnetic Resonance, Biomolecular
  • Motion
  • Molecular Sequence Data
  • Models, Molecular
  • Magnesium
  • Kinetics
  • HIV-1
  • Dimerization