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DNA stability: Difference between revisions
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(New page: Although DNA is generally viewed as a stable molecule, many conditions can cause loss of DNA bases or strand breakage. ==Depurination== * Depurination involves the loss of purine bases f...) |
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==Depurination== | ==Depurination== | ||
* Depurination involves the loss of purine bases forming abasic sites | * Depurination involves the loss of purine bases forming abasic sites | ||
* Depurination is one of the two limiting factors in chemical synthesis of long DNA oligos (the other is coupling efficiency) | * Depurination is one of the two limiting factors in chemical synthesis of long DNA oligos (the other is coupling efficiency) | ||
* DNA under physiological conditions has been | * DNA under physiological conditions has been estimated to depurinate at a rate of <math>3\cdot 10^{-11}</math>/sec at 37C and pH 7.4 <cite>lindahl72</cite> | ||
* Heating DNA for 10m@100 at pH 7.0 leads to about 1 apurinic site per 1000 base pairs | |||
* The activation energy of depurination is around 29 kcal/mol | |||
* Higher temperatures lead to faster depurination | |||
* Denatured DNA depurinates at about 4 times the rate of dsDNA @ pH 7.4 | |||
* Methylated As (6-methyladenine) found in bacteria are depurinated 4 times faster than the unmethylated purine bases | |||
* Depurination decreases at higher pH (thus acidic conditions favor depurination) | |||
* Depurination proceeds more rapidly in buffers of low ionic strength | |||
* Depurination is correlated with lower transformation efficiency | |||
* Depurination is independent of sequence | |||
==Deamination== | ==Deamination== | ||
