What happens when cytosine is deaminated?
Abstract. Spontaneous deamination converts cytosine to uracil, which is excised from DNA by the enzyme uracil-DNA glycosylase, leading to error-free repair.
Is deamination a mutation?
Deamination is removing the amino group from the amino acid and converting to ammonia. Since the bases cytosine, adenine and guanine have amino groups on them that can be deaminated, Deamination can cause mutation in DNA.
What is the meaning of deamination of 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.
Which base is generated by the deamination of 5 methylcytosine?
While spontaneous deamination of cytosine forms uracil, which is recognized and removed by DNA repair enzymes, deamination of 5-methylcytosine forms thymine. This conversion of a DNA base from cytosine (C) to thymine (T) can result in a transition mutation.
What is methylated cytosine?
Cytosine methylation is a common form of post-replicative DNA modification seen in both bacteria and eukaryotes. Modified cytosines have long been known to act as hotspots for mutations due to the high rate of spontaneous deamination of this base to thymine, resulting in a G/T mismatch.
What causes deamination of cytosine?
An active site glutamate promotes deamination of C4 and the conversion of cytosine analogs into uridine analogs (23). In addition to deamination of unmodified cytosine, some studies have suggested that mC deamination can generate thymine (22, 24).
What causes DNA deamination?
Cytosine deamination, like AP site formation, is caused by hydrolysis and is probably present in the DNA extracted from many sources. Interestingly, unlike depurination, the rate of cytosine deamination is slowed in double-stranded DNA as compared to single stranded DNA.
What is depurination and deamination?
Depurination; the hydrolytic removal of guanine or adenine from the #1 C (carbon) of deoxyribose in a DNA strand. Deamination: hydrolytic removal of amino (-NH2) groups from guanine (most common), cytosine or adenine. Oxidative damage of deoxyribose with any base, but most commonly purines.
What is the enzyme that convert cytosine to uracil?
Cytosine deaminase (CD) is an inducible enzyme expressed by Escherichia coli and certain fungi, not found in mammalian cells, and catalyzes the hydrolyic deamination of cytosine to uracil during times of nutritional stress.
What is a DNA mutation?
A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.
What are the methods used for mutation detection?
A wide range of methods has been used for mutation detection. Molecular methods for identification of the disease-causing mutations could be classified as methods for known and methods for unknown mutations.
What is a de novo mutation?
Mutations arising in parent’s germ cells are termed de novo mutations and can cause various inherited disorders. Errors in DNA can arise due to environmental factors or spontaneously, e.g. during DNA replication or due to deamination of 5-methylcytosine.
How are single base pair mutations identified in DNA sequencing?
In general, single base pair mutations are identified by direct sequencing, DNA hybridization and/or restriction enzyme digestion methods.