CHDI Conference 2017 Poster: Pursuit of a high resolution structure of full-length huntingtin by cryo-electron microscopy

Huntington’s disease is hallmarked by the CAG expansion of the huntingtin gene. How the corresponding polyQ expansion affects the structure of the encoded huntingtin protein remains poorly understood in the absence of a high resolution full-length protein structure. Huntingtin is a large, monomeric protein of 350 kDa, an ideal size for electron microscopy based structural biology methods. Using protein derived from a baculovirus expression system, we have successfully calculated a new protein envelope of huntingtin at ~15 Å resolution by negative stain electron microscopy. This reveals a claw-shaped molecule with a large central cavity. Grids of the protein sample have been optimized to produce a disperse array of homogenous protein particles in a fine vitreous ice layer for analysis by cryo-electron microscopy. A high resolution dataset has been collected on a Krios instrument and work is continuing in pursuit of this protein structure. This project is part of the open notebook labscribbles, through which methods and data are freely shared through the repository Zenodo under a CC-by license in real time in an effort to catalyse research in this area.