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Updated: Jun 7, 2026

High Resolution Physical Characterization of Single Metallic Nanoparticles
Published on: June 28, 2019
Effects of salts on internal DNA pressure and mechanical properties of phage capsids
Alex Evilevitch1, Wouter H Roos, Irena L Ivanovska
1Department of Physics, Carnegie Mellon University, PA 15213, USA. alexe@andrew.cmu.edu
Abstract:
Based on atomic force microscopy nanoindentation measurements of phage λ, we previously proposed a minimal model describing the effect of water hydrating DNA that strengthens viral capsids against external deformation at wild-type DNA packing density. Here, we report proof of this model by testing the prediction that DNA hydration forces can be dramatically decreased by addition of multivalent ions (Mg(2+) and Sp(4+)). These results are explained using a DNA hydration model without adjustable parameters. The model also predicts the stiffness of other DNA-filled capsids, which we confirm using bacteriophage ϕ29 and herpes simplex virus type 1 particles.
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