Complement component 9

The complement C9, also referred to as complement C9, is a protein of the complement system and has as a main component of the membrane attack complex to the immune system of humans and animals an important function. Mutations in the C9 gene responsible for rare inherited susceptibility to infection with Neisseria.

Genetics and construction

The gene coding for C9 C9 gene is located on chromosome 9 in human gene locus p13. It consists of eleven exons that - have a length of 100 to 250 base pairs - with the exception of exon 11. Exon 11 consists of about 1000 base pairs.

The gene consists of 537 amino acids. At the amino terminus C9 is composed substantially of hydrophilic amino acids, hydrophobic amino acids are mainly while at the carboxyl terminus. The amphiphilic structure is necessary to the membrane attack complex - form the 6-16 C9 units together with one C5b, C6, C7 and C8 unit - to allow penetration of the cell membrane of the target cell.

Diseases

C9 deficiency is one of the most commonly encountered genetic abnormalities in Japan. The incidence is 1 homozygote to 1000. In fair-skinned people, however, very few cases are known. Those affected are largely healthy, but have a significantly increased risk of suffering from meningococcal meningitis.

Further Reading

  • D. Marazziti include: Relationships Between The gene and protein structure in human complement component C9. In: Biochemistry 27, 1988, pp. 6529-6534. PMID 3219351
Complement membrane attack complex Gene product Neisseria meningitidis Entrez
483492
de