Jr. Harris et A. Holzenburg, HUMAN ERYTHROCYTE CATALASE - 2-D CRYSTAL NUCLEATION AND PRODUCTION OFMULTIPLE CRYSTAL FORMS, Journal of structural biology, 115(1), 1995, pp. 102-112
Negatively stained electron microscope images are presented, showing t
he nucleation of two-dimensional (2-D) crystals of human erythrocyte c
atalase produced on mica by the negative staining-carbon film techniqu
e. Examples of the formation of partially ordered 2-D arrays and more
ordered 2-D crystals are shown and the conditions required for the pro
duction of large well-ordered 2-D crystals discussed. The structural t
ransformation of one flexuous 2-D paracrystal into a p2 2-D crystal is
considered. The crystallographic 2-D image average of this p2 crystal
form is presented (lattice parameters a = 9.0 nm, b = 18.6 nm, gamma
= 90.8 degrees). It is shown that transmission electron microscopy pro
vides the possibility of defining 2-D crystal nucleation, growth of in
termediate forms, and low-resolution crystallographic structural analy
sis of 2-D crystals of human erythrocyte catalase. Comparison of the v
arious electron microscopical negatively stained images with the pepti
de backbone of the X-ray structure of bovine liver catalase at differe
nt tilt and rotation positions correlates with and emphasizes the mult
iple intermolecular contacts and orientations that can be adopted by h
uman erythrocyte catalase, leading to various 2-D arrays and 2-D cryst
als. Alignment of the surface groups involved in the protein-protein i
nteractions that occur during 2-D crystal nucleation and crystal growt
h may ultimately be determined. From this approach, when taken togethe
r with detailed consideration of protein-solvent and protein-solute el
ectrostatic interactions in solution, and at the fluid-air interface,
it is considered that a more general theory of crystal nucleation and
growth may eventually emerge. (C) 1995 Academic Press, Inc.