Jagota, M.; Townshend, R. J. L.; Kang, L.-W.; Bushnell, D. A.; Dror, R. O.; Kornberg, R. D. & Azubel, M. Gold nanoparticles and tilt pairs to assess protein flexibility by cryo-electron microscopy. Ultramicroscopy, 2021, 227, 113302
A computational method was developed to recover the three-dimensional coordinates of gold nanoparticles specifically attached to a protein complex from tilt-pair images collected by electron microscopy. The program was tested on a simulated dataset and applied to a real dataset comprising tilt-pair images recorded by cryo electron microscopy of RNA polymerase II in a complex with four gold-labeled single-chain antibody fragments. The positions of the gold nanoparticles were determined, and comparison of the coordinates among the tetrameric particles revealed the range of motion within the protein complexes.