Oi. Kiselyova et al., AFM study of membrane proteins, cytochrome P4502B4, and NADPH-cytochrome P450 reductase and their complex formation, ARCH BIOCH, 371(1), 1999, pp. 1-7
The application of the AFM technique for visualization of membrane proteins
and for measuring their dimensions was demonstrated. The AFM images of the
microsomal monooxygenase system components-cytochrome P450 2B4 and NADPH-c
ytochrome P450 reductase-were obtained by using two types of supports-hydro
phobic, highly oriented pyrolytic graphite (HOPG) and hydrophilic mica. It
was shown that hemo- and flavoprotein monomers and oligomers can be adsorbe
d to and visualized on HOPG. On the negatively charged mica matrix, flavopr
otein oligomers dissociated to monomers while hemoprotein oligomers dissoci
ated into less aggregated particles. The images of cytochrome P450 2B4 and
NADPH-cytochrome P450 reductase monomers were about 3 and 5 nm high, respec
tively, while the images of oligomeric forms of these proteins were about 1
0 and 8 nm high, respectively. We were able to observe the binary complexes
composed of monomeric proteins, cytochrome P450 2B4 and its reductase and
to measure the heights of these complexes (7 nm). The method is applicable
for visualization of not only individual proteins but also their complexes.
(C) 1999 Academic Press.