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Direct measurement of phage phi29 stiffness provides evidence of internal pressure
Mercedes Hernando-Pérez1, Roberto Miranda, María Aznar
1Dpto. Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049-Madrid, Spain.
Small (Weinheim an Der Bergstrasse, Germany)
|June 1, 2012
Abstract:
Using AFM nanoindentation experiments, DNA-full phi29 phage capsids are shown to be stiffer than when empty. The presence of counterions softens full viruses in a reversible manner, indicating that pressure originates from the confined DNA. A finite element analysis of the experiments provides an estimate of the pressure of ∼40 atm inside the capsid, which is similar to theoretical predictions.

