Recent Research Developments
|Index of Recent Research News|
The packaging of
nucleic acids, especially DNA, is of vital importance to all life-forms from viruses to multicellular
organisms. Human cells, for example, contain approximately 2
meters of DNA packed into a nucleus with a radius of 3 Ám. This
represents a million-fold reduction in the effective packing volume
of DNA in the nucleus relative to that in solution. In addition
to its role in the packaging of genetic material, DNA bending is also
important for the regulation of gene expression and protein-DNA
binding. It is of fundamental importance therefore to
understand the nature of the forces that govern the bending of
charged DNA molecules into non-linear structures and quantify the
magnitudes of their associated energetic factors.
Recently, the research group of Prof. Darrin York of the Department of
Chemistry along with graduate students Kevin
Range and Evelyn Mayaan, and in collaboration
with Prof. L.
James Maher, III of the Department of Biochemistry and
Molecular Biology, Mayo Clinic College
of Medicine, have studied the energetics of DNA bending with
In this work, a linear-scaling Green's function solvation method was employed, along with Monte Carlo simulation of counterion occupations at the phosphate residues, in order to quantify the preferential ion and solvation stabilization of bent versus linear DNA. From these calculations, they were able to predict that the electrostatic phosphate-phosphate contribution to DNA bending is on the order of 30 percent - a substantial, but not fully dominating effect. This work is featured on the cover of a recent issue of Nucleic Acids Research 33(4) 1257 (2005). A movie showing how the counterion distribution changes with ion load is also available.
|* This page is updated every two weeks.
Next scheduled update: April 27, 2005.
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