Deamination
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Deamination is the removal of an
this reaction are called deaminases.In the
Deamination reactions in DNA
Cytosine
Spontaneous deamination is the
In
5-methylcytosine
Spontaneous deamination of
Cytosine deamination increases C-To-T mutations
A known result of cytosine methylation is the increase of C-to-T transition mutations through the process of deamination. Cytosine deamination can alter the genome's many regulatory functions; previously silenced transposable elements (TEs) may become transcriptionally active due to the loss of CPG sites.[3] TEs have been proposed to accelerate the mechanism of enhancer creation by providing extra DNA that is compatible with the host transcription factors that eventually have an impact on C-to-T mutations.[3]
Guanine
Deamination of guanine results in the formation of xanthine. Xanthine, however, still pairs with cytosine.[4][5]
Adenine
Deamination of adenine results in the formation of hypoxanthine. Hypoxanthine, in a manner analogous to the imine tautomer of adenine, selectively base pairs with cytosine instead of thymine. This results in a post-replicative transition mutation, where the original A-T base pair transforms into a G-C base pair.
Additional proteins performing this function
- APOBEC1
- APOBEC3A-H, APOBEC3G - affects HIV
- Activation-induced cytidine deaminase (AICDA)
- Cytidine deaminase (CDA)
- dCMP deaminase (DCTD)
- AMP deaminase (AMPD1)
- Adenosine Deaminase acting on tRNA (ADAT)
- Adenosine Deaminase acting on dsRNA (ADAR)
- Double-stranded RNA-specific editase 1 (ADARB1)
- Adenosine Deaminase acting on mononucleotides (ADA)
- Guanine Deaminase (GDA)
See also
References
- ^ Smith, Michael B.; March, Jerry (2013), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (7th ed.), New York: Wiley-Interscience, p. 1547
- PMID 8662714.
- ^ PMID 32719115.
- ^ Tyagi, R. (2009). Understanding Genetics and Evolution: Discovery Publishing House.
- ^ Herriott, R. M. (1966). Mutagenesis. Cancer Research, 26(9 Part 1)