Using the Volta phase plate with defocus for cryo-EM single particle analysis

Abstract

Previously, we reported an in-focus data acquisition method for cryo-EM single particle analysis with the Volta phase plate (VPP) (Danev and Baumeister, 2016). Here, we extend the technique to include a small amount of defocus which enables contrast transfer function measurement and correction. This hybrid approach simplifies the experiment and increases the data acquisition speed. It also enables 3D reconstructions with resolutions in the 2 [A] range, demonstrating that, in practice, there are no resolution limitations imposed by the VPP.