Formation of Covalent Complexes between the Fourth Component of Human Complement and IgG Immune Aggregates

Complement ◽  
1987 ◽  
Vol 4 (1) ◽  
pp. 21-32 ◽  
Author(s):  
J.M. Alcolea ◽  
L.C. Antón ◽  
G. Marqués ◽  
P. Sánchez-Corral ◽  
F. Vivanco
Keyword(s):  
Human Complement ◽  
Fourth Component ◽  
Immune Aggregates

Production of Antibody Against the Fourth Component of Human Complement

Vox Sanguinis ◽  
1964 ◽  
Vol 9 (1) ◽  
pp. 91-95 ◽  
Author(s):  
Margaret J. Polley ◽  
Erna M. Rochna ◽  
P. L. Mollison
Keyword(s):  
Human Complement ◽  
Fourth Component

The primary structure of the fourth component of human complement (C4)-C-terminal peptides

1985 ◽  
Vol 5 (10-11) ◽  
pp. 913-921 ◽  
Author(s):  
S. K. Alex Law ◽  
Jean Gagnon
Keyword(s):  
Primary Structure ◽  
Protein Sequence ◽  
Human Complement ◽  
Cdna Sequencing ◽  
Complement C4 ◽  
Fourth Component ◽  
Polypeptide Chains ◽  
Complete Primary Structure

C-terminal CNBr peptides of the three polypeptide chains of C4 were obtained and sequenced. These results supplement previously obtained data, notably the protein sequence derived from cDNA sequencing of pro-C4 (Belt KT, Carroll MC & Porter RR (1984) Cell36, 907–914) and the N-terminal sequences of the three polypeptides (Gigli I, von Zabern I & Porter RR (1977) Biochem. J.165, 439–446), to define the complete primary structure of the plasma form of C4. The β (656 residues), α (748 residues), and γ (291 residues) chains are found in positions 1–656, 661–1408, and 1435–1725 in the pro-C4 molecule.

scholarly journals Amino acid sequence around the thiol and reactive acyl groups of human complement component C4

1981 ◽  
Vol 199 (2) ◽  
pp. 359-370 ◽  
Author(s):  
R D Campbell ◽  
J Gagnon ◽  
R R Porter
Keyword(s):  
Thiol Group ◽  
Ester Bond ◽  
Human Complement ◽  
Active Molecule ◽  
Free Thiol ◽  
Continuous Sequence ◽  
N Terminus ◽  
Free Thiol Group ◽  
Fourth Component ◽  
Human Complement Component

Activation of the fourth component of complement (C4) by C1s results in the generation of a reactive acyl group, able to react with putrescine, and in the release of a free thiol group that cannot be detected in the native haemolytically active molecule. Both the reactive acyl group and the free thiol group have been shown to reside in C4d, a fragment of the alpha′-chain of C4b derived from digestion of the molecule with the control proteins C3b inactivator and C4-binding protein. Peptides derived from CNBr digestion of [1,4-14C]putrescine-labelled and iodo(2-14C]acetic acid-labelled C4d have been obtained and used to establish a continuous sequence of 88 residues from the N-terminus of the molecule. The thiol and reactive acyl groups are contained in an octapeptide that shows near identity with the equivalent sequences reported for alpha 2-macroglobulin and C3. Other adjacent short sections also show homology of sequence between the three proteins, and it is highly likely that they contribute to the overall structure that gives a unique reactivity to the thiol ester bond postulated to exist in the native forms of the three proteins.

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