APOBEC3
| APOBEC3 | ||
|---|---|---|
| Cofactor | zinc | |
| Identifier | ||
| Gene name (s) | APOBEC3A , APOBEC3B , APOBEC3C , APOBEC3D , APOBEC3F , APOBEC3G , APOBEC3H , | |
| Enzyme classification | ||
| EC, category | 3.5.4.- , hydrolase | |
| Response type | hydrolysis | |
| Substrate | Deoxycytidine residue in foreign DNA | |
| Products | Deoxyuracil residue in foreign DNA | |
With APOBEC3 is an abbreviation referred APOBEC3 - proteins in which there are elements of the immune system to defend against retrovirus - infection is. The name comes from English and is an acronym for apo lipoprotein B mRNA editing enzyme catalytic polypeptide 3 . At least five APOBEC3 proteins are encoded in the genome of humans and other primates : APOBEC3A, C, B, F and G. In other mammals , however, only one APOBEC3 is found. APOBEC3 is packaged specifically in retroviral virions by the host cell and acts by deamination of dC residues to dU residues in the retroviral genome, which leads to G → A hypermutations and destabilization of the genetic material. Due to the damage to the genetic material, the virus is no longer able to reproduce. The APOBEC3 protein family, together with the potent restriction factor tetherin and TRIM5α, is an important part of innate antiviral immunity .
The viral structures that APOBEC3 recognizes on the virus particle are still unknown.
Retroviruses have mechanisms to escape the APOBEC3 effects, either by changing the peptide sequences recognized by APOBEC3 or, in the case of complex retroviruses, by coding accessory proteins that are specifically directed against certain APOBEC3 proteins, such as Vif in HIV or probably bet on foamy viruses . In human HIV infection, APOBEC3G and 3F play particularly important roles in this context, as these are primarily found in the affected CD4 helper cells and, accordingly, Vif also works specifically against them by binding to APOBEC3G and 3F and thereby incorporating them into prevents the virion and also supplies it to the cellular degradation machinery.
Individual evidence
- ^ Sara L. Sawyer, Michael Emerman, Harmit S. Malik: Ancient Adaptive Evolution of the Primate Antiviral DNA-Editing Enzyme APOBEC3G PLoS Biol . 2004 Sep; 2 (9): E275.
- ↑ Kirchhoff, F .: "Optimal" adaptation of pandemic HIV-1 strains to humans . In: BIOspectrum . 2, 2010, pp. 144-148.
- ↑ Tokarev, A. et al .: Antiviral activity of the interferon-induced cellular protein BST-2 / tetherin . In: AIDS Res Hum Retroviruses . 25, No. 12, December 2009, pp. 1197-1210. PMID 19929170 .