Metal ions and flexibility in a viral RNA pseudoknot at atomic resolution.

ABSTRACT: Many pathogenic viruses use programmed -1 ribosomal frameshifting to regulate translation of their structural and enzymatic proteins from polycistronic mRNAs. Frameshifting is commonly stimulated by a pseudoknot located downstream from a slippery sequence, the latter positioned at the ribosomal A and P sites. We report here the structures of two crystal forms of the frameshifting RNA pseudoknot from beet western yellow virus at resolutions of 1.25 and 2.85 A. Because of the very high resolution of 1.25 A, ten mono- and divalent metal ions per asymmetric unit could be identified, giving insight into potential roles of metal ions in stabilizing the pseudoknot. A magnesium ion located at the junction of the two pseudoknot stems appears to play a crucial role in stabilizing the structure. Beca

SUBMITTER: Egli M 

PROVIDER: S-EPMC123643 | biostudies-literature | 2002 Apr

REPOSITORIES: biostudies-literature