[1] Stanford Univ, Dept Chem Engn, Stanford, CA 94305 USA
[2] Stanford SLAG CryoEM Initiat, Stanford, CA 94305 USA
[3] Stanford Univ, Cell Sci Imaging Facil, Stanford, CA 94305 USA
[4] Stanford Univ, Sch Med, Dept Struct Biol, Stanford, CA 94305 USA
[5] Stanford Univ, Sch Med, Dept Mol & Cellular Physiol, Stanford, CA 94305 USA