Complement component C9
| Complement component C9 | ||
|---|---|---|
| Mass / length primary structure | 537 amino acids | |
| Identifier | ||
| Gene name (s) | C9 | |
| External IDs | ||
| Occurrence | ||
| Parent taxon | Animals | |
The complement component C9 , also known as complement factor C9 , is a protein of the complement system and, as the main component of the membrane attack complex, has an important function for the immune system of humans and animals. Mutations in the C9 - gene responsible for rare genetic susceptibility to infection with Neisseria .
Genetics and Construction
The C9 for coding C9 - gene is located in humans on chromosome 9 locus p13. It consists of eleven exons which - with the exception of exon 11 - have a length of 100 to 250 base pairs . Exon 11 consists of over 1000 base pairs.
The gene product consists of 537 amino acids . At the amino terminus , C9 is essentially composed of hydrophilic amino acids, while the carboxyl terminus contains mainly hydrophobic amino acids. The amphiphilic structure is necessary in order to enable the membrane attack complex - which form 6 to 16 C9 units together with one C5b , C6 , C7 and C8 unit - to penetrate the cell membrane of the target cell.
Diseases
C9 deficiency is one of the most common genetic abnormalities encountered in Japan . The incidence is 1 homozygous in 1000. In light-skinned people, however, only very few cases are known. Those affected are mostly healthy, but have a significantly increased risk of contracting meningococcal - Meningitis cancer.
further reading
- D. Marazziti et al: Relationships between the gene and protein structure in human complement component C9. In: Biochemistry 27, 1988, pp. 6529-6534. PMID 3219351
Individual evidence
- ↑ Homologues at inParanoid
- ^ S. Rogne et al.: The gene for human complement C9 is on chromosome 5. In: Genomics 5, 1989, pp. 149–152. PMID 2767685
- ↑ K. Witzel-Schlömp et al: The human complement C9 gene: identification of two mutations causing deficiency and revision in the gene structure. In: J Immun 158, 1997, pp. 5043-5049. PMID 9144525
- ↑ M. Nagata et al .: Inherited deficiency of ninth component of complement: an increased risk of meningococcal meningitis. In: J Pediat 114, 1989, pp. 260-264. PMID 2915285
Web links
- Complement component C9. In: Online Mendelian Inheritance in Man . (English)
- Complement component 9 ( Entrez Gene )
- de Bono / reactome: Creation of the Membrane Attack Complex (MAC)