help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Biophys. J. BioFAST: First Published July 22, 2005. doi:10.1529/biophysj.105.064667
© 2005 by the Biophysical Society.

A more recent version of this article appeared on October 1, 2005.
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
biophysj.105.064667v1
89/4/2558    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Podestá, A.
Right arrow Articles by Dunlap, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Podestá, A.
Right arrow Articles by Dunlap, D.

NUCLEIC ACIDS

Positively charged surfaces increase the flexibility of DNA

Alessandro Podestá 1, Marco Indrieri 1, Doriano Brogioli 1, Gerald Manning 2, Paolo Milani 1, Rosalinda Guerra 1, Laura Finzi 1 and David Dunlap 3*

1 University of Milan
2 Rutgers University
3 San Raffaele Scientific Institute

* To whom correspondence should be addressed. E-mail: dunlap.david{at}hsr.it.

Submitted on April 15, 2005
Revised on May 9, 2005
Accepted on 24 June 2005


  Abstract
Many proteins "bind" DNA through positively charged amino acids on their surfaces. However in order to overcome significant energetic and topological obstacles, proteins that bend or package DNA might also modulate the stiffness that is generated by repulsions between phosphates within DNA. Much previous work describes how ions change the flexibility of DNA in solution, but when considering macromolecules such as chromatin in which the DNA contacts the nucleosome core each turn of the double helix, it may be more appropriate to assess the flexibility of DNA on charged surfaces. Mica coated with positively charged molecules is a convenient substrate upon which the flexibility of DNA may be directly measured with a scanning force microscope. In the experiments described below, the flexibility of DNA increased as much as 5-fold depending on the concentration and type of polyamine used to coat mica. Using theory that relates charge neutralization to flexibility, we predict that phosphate repulsions were attenuated by approximately 50 % in the most flexible DNA observed. This simple method is an important tool for investigating the physiochemical causes and molecular biological effects of DNA flexibility, which affects DNA biochemistry ranging from chromatin stability to viral encapsulation.

Key Words: persistence length, poly-L-ornithine, polyamine, scanning probe microscopy, spermidine, worm-like chain




This article has been cited by other articles:


Home page
 Biophys. JHome page
F. Montel, E. Fontaine, P. St-Jean, M. Castelnovo, and C. Faivre-Moskalenko
Atomic Force Microscopy Imaging of SWI/SNF Action: Mapping the Nucleosome Remodeling and Sliding
Biophys. J., July 15, 2007; 93(2): 566 - 578.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
G. S. Manning
The Persistence Length of DNA Is Reached from the Persistence Length of Its Null Isomer through an Internal Electrostatic Stretching Force
Biophys. J., November 15, 2006; 91(10): 3607 - 3616.
[Abstract] [Full Text] [PDF]

Home page
 Nucleic Acids ResHome page
R. J. McDonald, J. D. Kahn, and L. J. Maher III
DNA bending by bHLH charge variants
Nucleic Acids Res., October 18, 2006; 34(17): 4846 - 4856.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
G. S. Manning
The Contribution of Transient Counterion Imbalances to DNA Bending Fluctuations
Biophys. J., May 1, 2006; 90(9): 3208 - 3215.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2005 by the Biophysical Society.