Published online 13 June 2005
Article |
Loss of GA base pairs is insufficient for achieving a large opening of U4 snRNA K-turn motif
Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry Am Fassberg 11, 37077 Göttingen, Germany
*To whom correspondence should be addressed. Tel: +49 551 2011382; Fax: +49 551 2011467; Email: tjovin{at}gwdg.de
Received March 2, 2005. Revised May 30, 2005. Accepted May 30, 2005.
Upon binding to the 15.5K protein, two tandem-sheared GA base pairs are formed in the internal loop of the kink-turn motif of U4 snRNA (Kt-U4). We have reported that the folding of Kt-U4 is assisted by protein binding. Unstable interactions that contribute to a large opening of the free RNA (ke motion) were identified using locally enhanced sampling molecular dynamics simulations, results that agree with experiments. A detailed analysis of the simulations reveals that the ke motion in Kt-U4 is triggered both by loss of GA base pairs in the internal loop and backbone flexibility in the stems. Essential dynamics show that the loss of GA base pairs is correlated along the first mode but anti-correlated along the third mode with the ke motion. Moreover, when enhanced sampling was confined to the internal loop, the RNA adopted an alternative conformation characterized by a sharper kink, opening of GA base pairs and modified stacking interactions. Thus, loss of GA base pairs is insufficient for achieving a large opening of the free RNA. These findings, supported by previously published RNA structure probing experiments, suggest that GA base pair formation occurs upon protein binding, thereby stabilizing a selective orientation of the stems.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
F. Razga, J. Koca, A. Mokdad, and J. Sponer Elastic properties of ribosomal RNA building blocks: molecular dynamics of the GTPase-associated center rRNA Nucleic Acids Res., June 9, 2007; 35(12): 4007 - 4017. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Liu and D. M.J. Lilley The role of specific 2'-hydroxyl groups in the stabilization of the folded conformation of kink-turn RNA RNA, February 1, 2007; 13(2): 200 - 210. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Spackova and J. Sponer Molecular dynamics simulations of sarcin-ricin rRNA motif Nucleic Acids Res., February 2, 2006; 34(2): 697 - 708. [Abstract] [Full Text] [PDF] |
||||

