Linked Life Data

11955006

Source:http://linkedlifedata.com/resource/pubmed/id/11955006

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2002-4-16
pubmed:abstractText
Understanding the linkage between Mg(2+) binding and RNA folding requires a proper theoretical model describing the energetics of Mg(2+) binding to the folded and unfolded states of RNA. Our current understanding of Mg(2+) binding to these different RNA states derives from empirical thermodynamic models that depend on a number of unjustified assumptions. We present a rigorous theoretical model describing the linkage between RNA folding and magnesium ion binding. In this model, based on the non-linear Poisson-Boltzmann (NLPB) equation, the stabilization of RNA by Mg(2+) arises from two distinct binding modes, diffuse binding and site binding. Diffusely bound Mg(2+) are described as an ensemble of hydrated ions that are attracted to the negative charge of the RNA. Site-bound Mg(2+) are partially desolvated ions that are attracted to electronegative pockets on the RNA surface. We explore two systems, yeast tRNA(Phe) and a 58-nucleotide rRNA fragment, with different Mg(2+) binding properties. The NLPB equation accurately describes both the stoichiometric and energetic linkage between Mg(2+) binding and RNA folding for both of these systems without requiring any fitted parameters in the calculation. Moreover, the NLPB model presents a well-defined physical description of how Mg(2+) binding helps fold an RNA. For both of the molecules studied here, the relevant unfolded state is a disordered intermediate state (I) that contains stable helical secondary structure without any tertiary contacts. Diffusely bound Mg(2+) interact with these secondary structure elements to stabilize the I state. The secondary structural elements of the I state fold into a compact, native tertiary structure (the N state). Diffuse binding plays a dominant role in stabilizing the N state for both RNAs studied. However, for the rRNA fragment, site-binding to a location with extraordinarily high electrostatic potential is also coupled to folding. Our results suggest that much experimental data measuring the linkage between Mg(2+) binding and RNA folding must be reinterpreted.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Elsevier Science Ltd.
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
317
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
507-21
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
The linkage between magnesium binding and RNA folding.
pubmed:affiliation
Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA. vmisra@umich.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't