2-DIMENSIONAL CRYSTALLIZATION OF PROTEINS ON MERCURY

A new technique to obtain two-dimensional (2D) crystals of proteins is reported. A clean surface of mercury was utilized for monolayer formation and crystallization of the protein. Two different proteins, ferritin from a horse spleen and F1-ATPase from a thermophilic bacterium (TF1), were crystallized on the clean surface of mercury in an oxygen atmosphere. Two dimensional crystals were analyzed by electron crystallography. Ferritin was found to form a hexagonal lattice with unit cell parameters a = b = 12 nm and γ = 60°. The 2D crystal of ferritin at a 2.0 nm resolution in negative stain revealed a subunit formation with P3m1 symmetry. TF1 also formed a hexagonal lattice with unit cell parameters a = b = 10 nm and γ = 60°. The reconstructed image of TF1 at a 1.8 nm resolution showed a ring structure with six peripheral constituents and minor components located in the middle hole. © 1990.