TY - JOUR
T1 - C5b-9 dimer
T2 - Isolation from complement lysed cells and ultrastructural identification with complement-dependent membrane lesions*
AU - Biesecker, Gregory
AU - Podack, Eckhard R.
AU - Halverson, Craig A.
AU - Müller-Eberhard, Hans J.
PY - 1979/2/1
Y1 - 1979/2/1
N2 - The membrane attack complex (MAC) of complement was extracted from the membranes of cells lysed by human complement and its properties were compared with those of the fluid phase complex SC5b-9. Upon sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunochemical analysis, the two isolated complexes had identical subunit compositions, except that the MAC lacked the S-protein. The sedimentation coefficient and molecular weight of the extracted and isolated MAC were, respectively, 33.5 S and 1.7 x 106 daltons, compared to 23 S and 1.0 x106 dalton for SC5b-9. Because the molecular weight of the MAC is approximately two times greater than that of C5b-9 (800,000 daltons), the MAC is considered the dimer of C5b-9. Under specified conditions, the 33.5 S dimer could be converted to the 23 S monomer without dissociation of subunits. The MAC had the electron microscopic appearance and dimensions that are characteristic for the complement produced ultrastructural membrane lesions. SC5b-9 had a different ultrastructure that is dissimilar to the morphology of the lesions. The isolated MAC could be reincorporated into phospholipid bilayers and assumed on the surface of the resultant lipid vesicles the orientation and appearance of typical complement lesions.
AB - The membrane attack complex (MAC) of complement was extracted from the membranes of cells lysed by human complement and its properties were compared with those of the fluid phase complex SC5b-9. Upon sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunochemical analysis, the two isolated complexes had identical subunit compositions, except that the MAC lacked the S-protein. The sedimentation coefficient and molecular weight of the extracted and isolated MAC were, respectively, 33.5 S and 1.7 x 106 daltons, compared to 23 S and 1.0 x106 dalton for SC5b-9. Because the molecular weight of the MAC is approximately two times greater than that of C5b-9 (800,000 daltons), the MAC is considered the dimer of C5b-9. Under specified conditions, the 33.5 S dimer could be converted to the 23 S monomer without dissociation of subunits. The MAC had the electron microscopic appearance and dimensions that are characteristic for the complement produced ultrastructural membrane lesions. SC5b-9 had a different ultrastructure that is dissimilar to the morphology of the lesions. The isolated MAC could be reincorporated into phospholipid bilayers and assumed on the surface of the resultant lipid vesicles the orientation and appearance of typical complement lesions.
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U2 - 10.1084/jem.149.2.448
DO - 10.1084/jem.149.2.448
M3 - Article
C2 - 762498
AN - SCOPUS:0018408322
VL - 149
SP - 448
EP - 458
JO - Journal of Experimental Medicine
JF - Journal of Experimental Medicine
SN - 0022-1007
IS - 2
ER -