The Molecular Foundry 1 article published in JoVE Environment Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy Matthew Rames1, Yadong Yu1, Gang Ren1 1Lawrence Berkeley National Laboratory, The Molecular Foundry More than half of proteins are small proteins (molecular mass <200 kDa) that are challenging for both electron microscope imaging and three-dimensional reconstructions. Optimized negative staining is a robust and high-throughput protocol to obtain high contrast and relatively high resolution (~1 nm) images of small asymmetric proteins or complexes under different physiological conditions.