Biomaterial Database

Partial amino acid sequences of the murine fourth component of complement (C4): demonstration of homology with human C4 and identification of the amino-terminal subunit in pro-C4. 1980

K L Parker, and D C Shreffler, and J D Capra

Radiolabeled murine C4 and C4 precursor (pro-C4) from cultured peritoneal macrophages were purified by immunoprecipitation and preparative gel electrophoresis. The partial NH2-terminal amino acid sequences of the isolated subunits demonstrated that murine C4 alpha, beta-, and gamma-chains all show sequence homology with the corresponding subunits of human C4; of the 10 residues identified in murine C4, all are identical to those in human C4. These data extend to the primary structural level the homology between the murine serum substance (Ss) protein and human C4. Comparisons of the amino acid sequences of murine pro-C4 and the constituent polypeptide chains of secreted C4 indicate that pro-C4 and the C4 beta-chain have an identical amino acid sequence. Both molecules have lysine at position 1, leucine at positions 4, 5, and 6, and phenylalanine at position 7. No sequence homology was found between pro-C4 and either the alpha- or gamma-subunits. These results define the beta-chain as the NH2-terminal subunit in the C4 precursor molecules.

UI	MeSH Term	Description	Entries
D011498	Protein Precursors		Precursors, Protein
D003181	Complement C4	A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.	C4 Complement,C4 Complement Component,Complement 4,Complement C4, Precursor,Complement Component 4,Pro-C4,Pro-complement 4,C4, Complement,Complement Component, C4,Complement, C4,Component 4, Complement,Component, C4 Complement,Pro C4,Pro complement 4
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013045	Species Specificity	The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.	Species Specificities,Specificities, Species,Specificity, Species
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular