The ''A''P2-''C''oincident ''D''omain mainly at the ''C''arboxy-terminus, or ACDC domain, is a
protein domain
In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist o ...
that occurs in proteins from
apicomplexan
The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. The ...
parasites.
It is found exclusively in apicomplexan proteins that also contain AP2 (
Apetala 2-integrase) DNA binding domains (ApiAP2 proteins). In 8 of 9 known examples in the
malarial
Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or deat ...
parasite ''
Plasmodium falciparum
''Plasmodium falciparum'' is a unicellular protozoan parasite of humans, and the deadliest species of ''Plasmodium'' that causes malaria in humans. The parasite is transmitted through the bite of a female '' Anopheles'' mosquito and causes the d ...
'' it is near the
carboxy terminus
The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...
, with the remaining one being at the
amino terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amin ...
. As yet, beyond its identification and the observation that it occurs only in ApiAP2 proteins, the function of the ACDC domain is unknown. Two proteins with the ACDC domain were found in the nucleus of ''P. falciparum'', as detected by a proteomic method, suggesting a role in nuclear biology.
References
{{Reflist
Protein domains