Electron Microscopy of Human Erythrocyte Catalase: New Two-Dimensional Crystal Forms

Abstract Using the mica-spreading "negative staining-carbon film" procedure, human erythrocyte catalase has been shown to create a number of different periodic or crystalline two-dimensional (2-D) arrays which differ in the arrangement of molecules in the repeating units and the lattice type. Digital image processing has been performed with a 2-D array which contains regularly arranged "undulating" rows of molecules and also with a 2-D crystal form, exhibiting pgg (p22 1 2 1 ) symmetry and lattice parameters of a = 12.7 nm, b = 44 nm, and γ= 92°. The data are compared with our previous analysis of a different human erythrocyte catalase 2-D crystal, and the effect of partial-depth negative s…