Open AccessMolecular goniometers for single-particle cryo-electron microscopy of DNA-binding proteins
Author(s) -
Tural Aksel,
Zanlin Yu,
Yifan Cheng,
Shawn M. Douglas
Publication year - 2020
Publication title -
nature biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 15.358
H-Index - 445
eISSN - 1546-1696
pISSN - 1087-0156
DOI - 10.1038/s41587-020-0716-8
Subject(s) - cryo electron microscopy , single particle analysis , goniometer , dna , particle (ecology) , dna origami , biophysics , microscopy , crystallography , electron microscope , structural biology , biological system , chemistry , physics , biology , optics , biochemistry , ecology , aerosol , organic chemistry
Correct reconstruction of macromolecular structure by cryo-electron microscopy (cryo-EM) relies on accurate determination of the orientation of single-particle images. For small (<100 kDa) DNA-binding proteins, obtaining particle images with sufficiently asymmetric features to correctly guide alignment is challenging. We apply DNA origami to construct molecular goniometers-instruments that precisely orient objects-and use them to dock a DNA-binding protein on a double-helix stage that has user-programmable tilt and rotation angles. We construct goniometers with 14 different stage configurations to orient and visualize the protein just above the cryo-EM grid surface. Each goniometer has a distinct barcode pattern that we use during particle classification to assign angle priors to the bound protein. We use goniometers to obtain a 6.5-Å structure of BurrH, an 82-kDa DNA-binding protein whose helical pseudosymmetry prevents accurate image orientation using traditional cryo-EM. Our approach should be adaptable to other DNA-binding proteins as well as small proteins fused to DNA-binding domains.