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56  structures 41  species 0  interactions 87  sequences 10  architectures

Family: APOBEC_C (PF05240)

Summary: APOBEC-like C-terminal domain

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This is the Wikipedia entry entitled "APOBEC". More...

APOBEC Edit Wikipedia article

Example of a member of the APOBEC family, APOBEC-2. A cytidine deaminase from Homo sapiens.[1]
APOBEC-like N-terminal domain
APOBEC-like C-terminal domain

APOBEC ("apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like") is a family of evolutionarily conserved cytidine deaminases.

A mechanism of generating protein diversity is mRNA editing. Members of this family are C-to-U editing enzymes. The N-terminal domain of APOBEC like proteins is the catalytic domain, while the C-terminal domain is a pseudocatalytic domain. More specifically, the catalytic domain is a zinc dependent cytidine deaminase domain and is essential for cytidine deamination. RNA editing by APOBEC-1 requires homodimerisation and this complex interacts with RNA binding proteins to form the editosome.[2]

In humans/mammals they help protect from viral infections.[3] These enzymes, when misregulated, are a major source of mutation in numerous cancer types.[3]

A 2013 review discussed the structural and biophysical aspects of APOBEC3 family enzymes.[4] Much of the APOBEC protein features are described in the widely studied APOBEC3G's page.

Family members

Human genes encoding members of the APOBEC protein family include:


  1. ^ PDB: 2NYT​; Prochnow, C.; Bransteitter, R.; Klein, M.G.; Goodman, M.F.; Chen, X.S.; functional implications for the deaminase AID. (2007). "The APOBEC-2 crystal structure". Nature. 445 (7126): 447–451. doi:10.1038/nature05492. PMID 17187054.; rendered using PyMOL.
  2. ^ Wedekind JE, Dance GS, Sowden MP, Smith HC (April 2003). "Messenger RNA editing in mammals: new members of the APOBEC family seeking roles in the family business". Trends Genet. 19 (4): 207–16. doi:10.1016/S0168-9525(03)00054-4. PMID 12683974.
  3. ^ a b "Unexpected DNA-Binding Mechanism Suggests Ways to Block Enzyme Activity in Cancer". Dec 2016. Based on ("Structural Basis for Targeted DNA Cytosine Deamination and Mutagenesis by APOBEC3A and APOBEC3B") online in Nature Structural and Molecular Biology.
  4. ^ Jaguva Vasudevan, AA; Smits SH; Höppner A; Häussinger D; Koenig BW; Münk C. (June 2013). "Structural features of antiviral DNA cytidine deaminases" (PDF). Biol. Chem. 394 (11): 1357–1370. doi:10.1515/hsz-2013-0165. PMID 23787464.
This article incorporates text from the public domain Pfam and InterPro: IPR013158

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

APOBEC-like C-terminal domain Provide feedback

This domain is found at the C-termini of the Apolipoprotein B mRNA editing enzyme.

Internal database links

This tab holds annotation information from the InterPro database.

No InterPro data for this Pfam family.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan CDA (CL0109), which has the following description:

This clan contains both free nucleotide and nucleic acid deaminases that act on adenosine, cytosine, guanine and cytidine, and are collectively known as the deaminase superfamily. The conserved fold consists of a three-layered alpha/beta/alpha structure with 3 helices and 4 strands in the 2134 order [1,2].This superfamily is further divided into two major divisions based on the presence of a helix (helix-4) that renders the terminal strands (strands 4 and 5) either parallel to each other in its presence, or anti-parallel in its absence [2]. Structurally, the deaminase-like fold is present in four other superfamilies including the JAB-like metalloproteins, the C-terminal AICAR transformylase-catalyzing domains of PurH, Tm1506 and the formate dehydrogenase accessory subunit FdhD. The active site of the deaminases is composed of three residues that coordinate a zinc ion between conserved helices 2 and 3. The residues are typically found as [HCD]xE and CxxC motifs at the beginning of helices 2 and 3. The zinc ion activates a water molecule, which forms a tetrahderal intermediate with the carbon atom that is linked to the amine group. This is followed by deamination of the base.

The clan contains the following 33 members:

A_deamin AICARFT_IMPCHas AID APOBEC1 APOBEC2 APOBEC3 APOBEC4 APOBEC4_like APOBEC_C APOBEC_N Bd3614-deam DAAD dCMP_cyt_deam_1 dCMP_cyt_deam_2 DddA-like DYW_deaminase FdhD-NarQ Inv-AAD LmjF365940-deam LpxI_C MafB19-deam NAD1 NAD2 OTT_1508_deam Pput2613-deam SNAD1 SNAD2 SNAD3 SNAD4 TM1506 Toxin-deaminase XOO_2897-deam YwqJ-deaminase


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

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HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

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Seed source: Pfam-B01590
Previous IDs: none
Type: Domain
Sequence Ontology: SO:0000417
Author: Yeats C
Number in seed: 75
Number in full: 87
Average length of the domain: 75.50 aa
Average identity of full alignment: 36 %
Average coverage of the sequence by the domain: 33.61 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.6 23.6
Trusted cut-off 23.7 23.7
Noise cut-off 23.4 23.4
Model length: 78
Family (HMM) version: 17
Download: download the raw HMM for this family

Species distribution

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Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the APOBEC_C domain has been found. There are 56 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
F8W3Q7 View 3D Structure Click here
P31941 View 3D Structure Click here
P41238 View 3D Structure Click here
P51908 View 3D Structure Click here
Q9HC16 View 3D Structure Click here
Q9UH17 View 3D Structure Click here
Q9Y235 View 3D Structure Click here