Microscopic Basis for the Mesoscopic Extensibility of Dendrimer-Compacted DNA

The mechanism of DNA compaction by dendrimers is key to the design of nanotechnologies that can deliver genetic material into cells. We present atomistic simulations, mesoscopic modeling and single-molecule pulling experiments describing DNA dendrimer interactions. All-atom molecular dynamics were u...

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Bibliographic Details
Published in:Biophysical journal 2010-03, Vol.98 (5), p.834-842
Main Authors: Mills, Maria, Orr, Brad, Banaszak Holl, Mark M., Andricioaei, Ioan
Format: Article
Language:English
Subjects:
Biophysics
Cells
Dendrimers - chemistry
Dendrimers - metabolism
Deoxyribonucleic acid
DNA
DNA - chemistry
DNA - metabolism
Microscopy - methods
Molecules
Monte Carlo simulation
Nanotechnology
Nucleic Acid
Thermodynamics
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Summary:The mechanism of DNA compaction by dendrimers is key to the design of nanotechnologies that can deliver genetic material into cells. We present atomistic simulations, mesoscopic modeling and single-molecule pulling experiments describing DNA dendrimer interactions. All-atom molecular dynamics were used to characterize pulling-force-dependent interactions between DNA and generation-3 PAMAM amine-terminated dendrimers, and a free energy profile and mean forces along the interaction coordinate are calculated. The energy, force, and geometry parameters computed at the atomic level are input for a Monte Carlo model yielding mesoscopic force-extension curves. Actual experimental single-molecule curves obtained with optical tweezers are also presented, and they show remarkable agreement with the virtual curves from our model. The calculations reveal the microscopic origin of the hysteresis observed in the phase transition underlying compaction. A broad range of ionic and pulling parameters is sampled, and suggestions for windows of conditions to probe new single-molecule behavior are made.
ISSN:0006-3495
1542-0086
DOI:10.1016/j.bpj.2009.11.020