Linked Life Data

9636066

Source:http://linkedlifedata.com/resource/pubmed/id/9636066

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
1998-7-20
pubmed:abstractText
The theophylline-binding RNA aptamer contains a 15 nucleotide motif that is required for high-affinity ligand binding. One residue within this RNA motif is only semiconserved and can be an A or C. This residue, C27, was disordered in the previously determined three-dimensional structure of the complex, suggesting that it is dynamic in solution. 13C Relaxation measurements are reported here, demonstrating that C27 is highly dynamic in the otherwise well-ordered RNA-theophylline complex. A synthetic complex with an abasic residue at position 27 was found to exhibit wild-type binding affinity (Kd approximately 0.2 microM), indicating that the base of residue 27 is not directly involved with theophylline binding. Surprisingly, the U27 and G27 RNAs were found to bind theophylline with low affinity (Kd values > 4 microM). NMR spectroscopy on the U27 RNA revealed the presence of an A7-U27 base pair in the free RNA that prevents formation of a critical base-platform structural motif and therefore blocks theophylline binding. Similarly, a protonated A7H+-C27 base pair forms in the absence of theophylline at low pH, which explains the unusual pH dependence of theophylline binding of the C27 RNA aptamer. Thus the weak binding for various nucleotides at position 27 arises not from unfavorable interactions in the RNA-theophylline complex but instead from stable interactions in the free state of the RNA that inhibit theophylline binding.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9186-92
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
A semiconserved residue inhibits complex formation by stabilizing interactions in the free state of a theophylline-binding RNA.
pubmed:affiliation
Department of Chemistry and Biochemistry, University of Colorado at Boulder 80309-0215, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.