|
||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The Journal of Cell Biology, Vol 97, 618-626, Copyright © 1983 by The Rockefeller University Press
ARTICLES |
J Tranum-Jensen and S Bhakdi
The structure and membrane insertion of the human C5b-9(m) complex, generated by lysis of antibody-coated sheep erythrocytes with whole human serum under conditions where high numbers of classical ring- shaped lesions form, were studied in single and complementary freeze- fracture replicas prepared by unidirectional and rotary shadowing. The intramembrane portion of the C5b-9(m) cylinder was seen on EF-faces as an elevated, circular structure. In nonetched fractures it appeared as a solid stub; in etched fractures a central pit confirmed the existence of a central, water-filled pore in the molecule. Complementary replicas showed that each EF-face ring corresponded to a hole in the lipid plateau of the PF-face. Etched fractures of proteolytically stripped membranes revealed the extramembrane annulus of the C5b-9(m) cylinder on ES-faces and putative internal openings on PS-faces. Allowing for the measured thickness of deposited Pt/C, the dimensions of EF-face rings and ES-face annuli conformed to anticipations derived from negatively stained preparations. Our results support the concept that the hollow cylindrical C5b-9(m) complex penetrates into the inner leaflet of the target erythrocyte membrane bilayer, forming a stable transmembrane protein channel.
This article has been cited by other articles:
|
|