ELECTRON-MICROSCOPY OF HUMAN ERYTHROCYTE CATALASE - NEW 2-DIMENSIONAL CRYSTAL FORMS

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, exhibitingpgg (p22121) 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 staining occurring in all the various 2-D forms is discussed. © 1993 Academic Press, Inc.