Determination of Rigidity of Protein Bound Au(144) Clusters by Electron Cryomicroscopy.

Abstract

A method for estimating the positional displacement of protein bound gold nanoparticles is presented and used to estimate the rigidity of linkage of Au144 nanoparticles bound to a tetrameric model protein. We observe a distribution of displacement values where most Au144 clusters are immobilized to within 3 Å relative to the protein center of mass. The shape of the distribution suggests two physical processes of thermal motion and protein deformation. The application of this and similar rigid gold nanoparticle/protein conjugates in high resolution single particle electron cryo-microscopy is discussed. © 2010 American Chemical Society.