Mg2+-induced variations in the conformation and dynamics of HIV-1 TAR RNA probed using NMR residual dipolar couplings.

Published

Journal Article

The effects of divalent Mg(2+) on the conformation and dynamics of the stem-loop transactivation response element (TAR) RNA from HIV-1 have been characterized using NMR residual dipolar couplings (RDCs). Order matrix analysis of one bond 13C-1H RDCs measured in TAR at [Mg(2+)]:[TAR] stoichiometric ratios of approximately 3:1 (TAR(3.0Mg)) and approximately 4.5:1 (TAR(4.5Mg)) revealed that Mg(2+) reduces the average inter-helical angle from 47(+/-5) degrees in TAR(free) to 5(+/-7) degrees in TAR(4.5Mg). In contrast to the TAR(free) state, the generalized degree of order for the two stems in TAR(4.5Mg) is found to be identical within experimental uncertainty, indicating that binding of Mg(2+) leads to an arrest of inter-helical motions in TAR(free). Results demonstrate that RDC-NMR methodology can provide new insight into the effects of Mg(2+) on both the conformation and dynamics of RNA.

Full Text

Duke Authors

Cited Authors

  • Al-Hashimi, HM; Pitt, SW; Majumdar, A; Xu, W; Patel, DJ

Published Date

  • June 20, 2003

Published In

Volume / Issue

  • 329 / 5

Start / End Page

  • 867 - 873

PubMed ID

  • 12798678

Pubmed Central ID

  • 12798678

International Standard Serial Number (ISSN)

  • 0022-2836

Digital Object Identifier (DOI)

  • 10.1016/s0022-2836(03)00517-5

Language

  • eng

Conference Location

  • England