TY - JOUR
T1 - Glutathione-catalyzed disulfide-linking of C9 in the membrane attack complex of complement
AU - Yamamoto, K.
AU - Kawashima, T.
AU - Migita, S.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1982
Y1 - 1982
N2 - The membrane attack complex of complement (the dimeric C5b-9 complex) is a multimolecular assemblage of five proteins (C5b, C6, C7, C8, and C9) which are held together by noncovalent forces. We found that C9 molecules in the complex can be covalently cross-linked (disulfide-linked) by glutathione. In this experiment, the tetramolecular C5b-8 complex bound to phospholipid vesicles was first prepared from purified C5b-6, C7, and C8. The vesicle-bound C5b-8 complex was then incubated (37°C, 20 min) with an excess of 131I-C9 in the presence of 1 mM glutathione; an average of 5.3 molecules of C9 per C5b-8 were bound and the C5b-9 complex formed was predominantly a dimeric C5b-9 complex. About one-third of C9 in this C5b-9 complex was found to be in a disulfide-linked dimeric form. The C5b-9 complex, having only a average of 0.9 molecules of C9 per C5b-8, was also prepared in the presence of glutathione; this C5b-9 preparation contained both monomeric and dimeric C5b-9 complexes, and about one-fifth of the C9 subunits was in a cross-linked dimeric form. By contrast, C9 in the absence of the C5b-8 complex was not significantly cross-linked by glutathione. These results indicate that C9 has a unique property to associate with itself upon reaction with the C5b-8 complex.
AB - The membrane attack complex of complement (the dimeric C5b-9 complex) is a multimolecular assemblage of five proteins (C5b, C6, C7, C8, and C9) which are held together by noncovalent forces. We found that C9 molecules in the complex can be covalently cross-linked (disulfide-linked) by glutathione. In this experiment, the tetramolecular C5b-8 complex bound to phospholipid vesicles was first prepared from purified C5b-6, C7, and C8. The vesicle-bound C5b-8 complex was then incubated (37°C, 20 min) with an excess of 131I-C9 in the presence of 1 mM glutathione; an average of 5.3 molecules of C9 per C5b-8 were bound and the C5b-9 complex formed was predominantly a dimeric C5b-9 complex. About one-third of C9 in this C5b-9 complex was found to be in a disulfide-linked dimeric form. The C5b-9 complex, having only a average of 0.9 molecules of C9 per C5b-8, was also prepared in the presence of glutathione; this C5b-9 preparation contained both monomeric and dimeric C5b-9 complexes, and about one-fifth of the C9 subunits was in a cross-linked dimeric form. By contrast, C9 in the absence of the C5b-8 complex was not significantly cross-linked by glutathione. These results indicate that C9 has a unique property to associate with itself upon reaction with the C5b-8 complex.
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M3 - Article
C2 - 7096325
AN - SCOPUS:0020265808
VL - 257
SP - 8573
EP - 8576
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 15
ER -