Structural highlights
Function
[ABEC2_HUMAN] Probable C to U editing enzyme whose physiological substrate is not yet known. Does not display detectable apoB mRNA editing. Has a low intrinsic cytidine deaminase activity. May play a role in the epigenetic regulation of gene expression through the process of active DNA demethylation.[1]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
APOBEC-2 (APO2) belongs to the family of apolipoprotein B messenger RNA-editing enzyme catalytic (APOBEC) polypeptides, which deaminates mRNA and single-stranded DNA. Different APOBEC members use the same deamination activity to achieve diverse human biological functions. Deamination by an APOBEC protein called activation-induced cytidine deaminase (AID) is critical for generating high-affinity antibodies, and deamination by APOBEC-3 proteins can inhibit retrotransposons and the replication of retroviruses such as human immunodeficiency virus and hepatitis B virus. Here we report the crystal structure of APO2. APO2 forms a rod-shaped tetramer that differs markedly from the square-shaped tetramer of the free nucleotide cytidine deaminase, with which APOBEC proteins share considerable sequence homology. In APO2, two long alpha-helices of a monomer structure prevent the formation of a square-shaped tetramer and facilitate formation of the rod-shaped tetramer via head-to-head interactions of two APO2 dimers. Extensive sequence homology among APOBEC family members allows us to test APO2 structure-based predictions using AID. We show that AID deamination activity is impaired by mutations predicted to interfere with oligomerization and substrate access. The structure suggests how mutations in patients with hyper-IgM-2 syndrome inactivate AID, resulting in defective antibody maturation.
The APOBEC-2 crystal structure and functional implications for the deaminase AID.,Prochnow C, Bransteitter R, Klein MG, Goodman MF, Chen XS Nature. 2007 Jan 25;445(7126):447-51. Epub 2006 Dec 24. PMID:17187054[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Guo JU, Su Y, Zhong C, Ming GL, Song H. Hydroxylation of 5-methylcytosine by TET1 promotes active DNA demethylation in the adult brain. Cell. 2011 Apr 29;145(3):423-34. doi: 10.1016/j.cell.2011.03.022. Epub 2011 Apr, 14. PMID:21496894 doi:10.1016/j.cell.2011.03.022
- ↑ Prochnow C, Bransteitter R, Klein MG, Goodman MF, Chen XS. The APOBEC-2 crystal structure and functional implications for the deaminase AID. Nature. 2007 Jan 25;445(7126):447-51. Epub 2006 Dec 24. PMID:17187054 doi:10.1038/nature05492
