Abstract
The three-dimensional structure of recombinants of the isolated membrane attack complex (MAC) of complement with single bilayer dioleoyllecithin (DOL) vesicles and with dimyristoyllecithin (DML) vesicles was determined. A total of four MAC-vesicle complexes were analyzed by imaging negatively stained specimens at various defined tilting angles under minimal dose conditions in the electron microscope and by computer-aided three-dimensional reconstruction. The information on electron micrographs obtained at 6° angular increments from +60° to -60° was digitized by densitometric scanning, Fourier-transformed, corrected for imaging errors, cross-correlated, and synthesized to the three-dimensional image. All four MAC-vesicle recombinants showed stain penetration into the interior of the vesicle, indicating increased permeability of the bilayer to negative stain. The MAC appeared as a hollow structure of 16-nm height, 2.0-nm wall thickness, and a 3.0-nm torus at the free end with an outer and inner diameter of 20.0 nm and 10.0 nm. In MAC-DOL vesicles the hollow core of the MAC terminated at the membrane-binding site, and only small pores of up to 2.0 nm in diameter penetrated the bilayer. In one MAC-DML vesicle lipid discontinuities on the outer circumference of the MAC binding site mediated stain penetration. The second MAC-DML vesicle showed a channel of ~4.0 nm connecting the hollow core of the MAC across the bilayer with the vesicle interior. The results suggest the MAC may mediate increased membrane permeability by protein channel formation in addition to lipid reorientation.
| Original language | English |
|---|---|
| Pages (from-to) | 2353-2357 |
| Number of pages | 5 |
| Journal | Journal of Immunology |
| Volume | 128 |
| Issue number | 5 |
| State | Published - Jan 1 1982 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Immunology
Cite this
Membrane attack complex of complement (MAC) : Three-dimensional analysis of MAC-phospholipid vesicle recombinants. / Podack, E. R.; Muller-Eberhard, H. J.; Horst, H.; Hoppe, W.
In: Journal of Immunology, Vol. 128, No. 5, 01.01.1982, p. 2353-2357.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Membrane attack complex of complement (MAC)
T2 - Three-dimensional analysis of MAC-phospholipid vesicle recombinants
AU - Podack, E. R.
AU - Muller-Eberhard, H. J.
AU - Horst, H.
AU - Hoppe, W.
PY - 1982/1/1
Y1 - 1982/1/1
N2 - The three-dimensional structure of recombinants of the isolated membrane attack complex (MAC) of complement with single bilayer dioleoyllecithin (DOL) vesicles and with dimyristoyllecithin (DML) vesicles was determined. A total of four MAC-vesicle complexes were analyzed by imaging negatively stained specimens at various defined tilting angles under minimal dose conditions in the electron microscope and by computer-aided three-dimensional reconstruction. The information on electron micrographs obtained at 6° angular increments from +60° to -60° was digitized by densitometric scanning, Fourier-transformed, corrected for imaging errors, cross-correlated, and synthesized to the three-dimensional image. All four MAC-vesicle recombinants showed stain penetration into the interior of the vesicle, indicating increased permeability of the bilayer to negative stain. The MAC appeared as a hollow structure of 16-nm height, 2.0-nm wall thickness, and a 3.0-nm torus at the free end with an outer and inner diameter of 20.0 nm and 10.0 nm. In MAC-DOL vesicles the hollow core of the MAC terminated at the membrane-binding site, and only small pores of up to 2.0 nm in diameter penetrated the bilayer. In one MAC-DML vesicle lipid discontinuities on the outer circumference of the MAC binding site mediated stain penetration. The second MAC-DML vesicle showed a channel of ~4.0 nm connecting the hollow core of the MAC across the bilayer with the vesicle interior. The results suggest the MAC may mediate increased membrane permeability by protein channel formation in addition to lipid reorientation.
AB - The three-dimensional structure of recombinants of the isolated membrane attack complex (MAC) of complement with single bilayer dioleoyllecithin (DOL) vesicles and with dimyristoyllecithin (DML) vesicles was determined. A total of four MAC-vesicle complexes were analyzed by imaging negatively stained specimens at various defined tilting angles under minimal dose conditions in the electron microscope and by computer-aided three-dimensional reconstruction. The information on electron micrographs obtained at 6° angular increments from +60° to -60° was digitized by densitometric scanning, Fourier-transformed, corrected for imaging errors, cross-correlated, and synthesized to the three-dimensional image. All four MAC-vesicle recombinants showed stain penetration into the interior of the vesicle, indicating increased permeability of the bilayer to negative stain. The MAC appeared as a hollow structure of 16-nm height, 2.0-nm wall thickness, and a 3.0-nm torus at the free end with an outer and inner diameter of 20.0 nm and 10.0 nm. In MAC-DOL vesicles the hollow core of the MAC terminated at the membrane-binding site, and only small pores of up to 2.0 nm in diameter penetrated the bilayer. In one MAC-DML vesicle lipid discontinuities on the outer circumference of the MAC binding site mediated stain penetration. The second MAC-DML vesicle showed a channel of ~4.0 nm connecting the hollow core of the MAC across the bilayer with the vesicle interior. The results suggest the MAC may mediate increased membrane permeability by protein channel formation in addition to lipid reorientation.
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UR - http://www.scopus.com/inward/citedby.url?scp=0020002246&partnerID=8YFLogxK
M3 - Article
C2 - 6174630
AN - SCOPUS:0020002246
VL - 128
SP - 2353
EP - 2357
JO - Journal of Immunology
JF - Journal of Immunology
SN - 0022-1767
IS - 5
ER -