Linked Life Data

14507713

Source:http://linkedlifedata.com/resource/pubmed/id/14507713

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2003-9-25
pubmed:abstractText
The adsorption of DNA molecules onto a flat mica surface is a necessary step to perform atomic force microscopy studies of DNA conformation and observe DNA-protein interactions in physiological environment. However, the phenomenon that pulls DNA molecules onto the surface is still not understood. This is a crucial issue because the DNA/surface interactions could affect the DNA biological functions. In this paper we develop a model that can explain the mechanism of the DNA adsorption onto mica. This model suggests that DNA attraction is due to the sharing of the DNA and mica counterions. The correlations between divalent counterions on both the negatively charged DNA and the mica surface can generate a net attraction force whereas the correlations between monovalent counterions are ineffective in the DNA attraction. DNA binding is then dependent on the fractional surface densities of the divalent and monovalent cations, which can compete for the mica surface and DNA neutralizations. In addition, the attraction can be enhanced when the mica has been pretreated by transition metal cations (Ni(2+), Zn(2+)). Mica pretreatment simultaneously enhances the DNA attraction and reduces the repulsive contribution due to the electrical double-layer force. We also perform end-to-end distance measurement of DNA chains to study the binding strength. The DNA binding strength appears to be constant for a fixed fractional surface density of the divalent cations at low ionic strength (I < 0.1 M) as predicted by the model. However, at higher ionic strength, the binding is weakened by the screening effect of the ions. Then, some equations were derived to describe the binding of a polyelectrolyte onto a charged surface. The electrostatic attraction due to the sharing of counterions is particularly effective if the polyelectrolyte and the surface have nearly the same surface charge density. This characteristic of the attraction force can explain the success of mica for performing single DNA molecule observation by AFM. In addition, we explain how a reversible binding of the DNA molecules can be obtained with a pretreated mica surface.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-11718557, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-12127449, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-12458218, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-12524295, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-2080421, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-353876, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-7696484, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-7809148, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-8785352, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-8799111, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-8800476, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-9000621, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-9113978, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-9121578, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-9547265, http://linkedlifedata.com/resource/pubmed/commentcorrection/14507713-9635738
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-3495
pubmed:author
pubmed:issnType
Print
pubmed:volume
85
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2507-18
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Adsorption of DNA to mica mediated by divalent counterions: a theoretical and experimental study.
pubmed:affiliation
Laboratoire Milieux Nanométriques, Université d'Evry, 91025 Evry Cedex, France.
pubmed:publicationType
Journal Article, Comparative Study, Evaluation Studies, Validation Studies