Nucleic Acids Research, Vol 24, Issue 20 4015-4022, Copyright © 1996 by Oxford University Press
JE Kanyo, J Duhamel and P Lu
The oligonucleotide r(GGACUUCGGUCC) has been observed to adopt a hairpin
conformation by solution NMR and a double helical conformation by X-ray
diffraction. In order to understand this apparent conflict, we used
time-resolved fluorescence depolarization and 19fluorine NMR to follow the
secondary structure of this dodecamer as the solution composition was
changed stepwise from the NMR experimental conditions to those used for
crystallization. Calculation of the dodecamer concentration in the crystal
(180 mM strands) and the cation concentration needed for neutrality (>2
M) prompted investigation of a tethered species, in which two dodecamers
are connected by a string of 4 nt, geometrically equivalent to
approximately 100 mM strands, in 2.5 M NaCl. The RNA tetraloop and its DNA
analog maintain a single-strand hairpin conformation in solution, even
under the conditions used to grow the crystal. Under high salt conditions,
the tethered RNA and DNA analogs of this sequence yield secondary
components which could be the double helical conformation. Crystal contacts
in addition to solvent changes and high RNA concentrations are needed to
obtain the double helix as the predominant species.
ARTICLES
Secondary structure of the r(CUUCGG) tetraloop
Department of Chemistry, University of Pennsylvania, Philadelphia 19104- 6323, USA.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
M. Olejniczak, Z. Gdaniec, A. Fischer, T. Grabarkiewicz, L. Bielecki, and R. W. Adamiak The bulge region of HIV-1 TAR RNA binds metal ions in solution Nucleic Acids Res., October 1, 2002; 30(19): 4241 - 4249. [Abstract] [Full Text] [PDF] |
||||
