Physics

Nanotechnology

Organic chemistry

Streptavidin

Single particle analysis

Crystallography

Biology

Optics

Biophysics

Resolution (logic)

Artificial intelligence

Chemical physics

Cryo-electron microscopy

Chemistry

Ecology

Materials science

Macromolecule

Biotin

Particle (ecology)

Aerosol

Graphene

Molecule

Computer science

Electron microscope

Angstrom

Biochemistry

Nature Communications

The fast development of single-particle cryogenic electron microscopy (cryo-EM) has made it more feasible to obtain the 3D structure of well-behaved macromolecules with a molecular weight higher than 300 kDa at ~3 Å resolution. However, it remains a challenge to obtain the high-resolution structures of molecules smaller than 200 kDa using single-particle cryo-EM. In this work, we apply the Cs-corrector-VPP-coupled cryo-EM to study the 52 kDa streptavidin (SA) protein supported on a thin layer of graphene and embedded in vitreous ice. We are able to solve both the apo-SA and biotin-bound SA structures at near-atomic resolution using single-particle cryo-EM. We demonstrate that the method has the potential to determine the structures of molecules as small as 39 kDa.

Single particle cryo-EM reconstruction of 52 kDa streptavidin at 3.2 Angstrom resolution