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NH2-terminal structure and cleavage of guinea pig pro-C3, the precursor of the third complement component

NH2-terminal structure and cleavage of guinea pig pro-C3, the precursor of the third complement component

Authors :
J Williams
H R Colten
B.F. Tack
G Goldberger
G N Abraham
M.L. Thomas
Source :
Journal of Biological Chemistry. 256:12617-12619
Publication Year :
1981
Publisher :
Elsevier BV, 1981.

Abstract

The NH2-terminal structures of the intracellular precursor of the third component of guinea pig complement (pro-C3), synthesized in macrophage cultures, and beta chain of C3 from guinea pig plasma were determined. Six of the first 16 residues of pro-C3 were identified by a microradiosequencing method. All six are nonpolar and are identical with the residues in beta chain of native plasma C3. This establishes beta chain as the NH2-terminal subunit in pro-C3. A comparison of primary structures of guinea pig and human C3 beta chains revealed identity of at least 8 residues within the NH2-terminal decapeptide. Incubation of plasmin with radiolabeled pro-C3 in macrophage lysate resulted in loss of pro-C3 and the generation of a two-chain molecule electrophoretically indistinguishable from native C3. These data indicate similarities between pro-C3 and the precursor of the fourth complement component, pro-C4, with respect to subunit organization, presence of phylogenetically conserved NH2-terminal regions, and the probable mechanism for generation of their respective native proteins.

Details

ISSN :
00219258
Volume :
256
Database :
OpenAIRE
Journal :
Journal of Biological Chemistry
Accession number :
edsair.doi...........a522843191810f7951790ef3b84b1e01
Full Text :
https://doi.org/10.1016/s0021-9258(18)42933-x