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DNA stability: Difference between revisions
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==Strand cleavage== | ==Strand cleavage== | ||
* Under physiological conditions (pH 7.4, ionic strength of 150mM with 10mM Mg++ ions), the lifetime of a phosphodiester bond at an abasic site is 190 hours @ 37C <cite>lindahl72b</cite> | |||
* Abasic sites are alkali-labile. Under mildly alkaline conditions, β-elimination occurs which nicks 3' to the abasic site leaving a 5'-P on the downstream fragment | * Abasic sites are alkali-labile. Under mildly alkaline conditions, β-elimination occurs which nicks 3' to the abasic site leaving a 5'-P on the downstream fragment | ||
* Under strong alkaline conditions, δ-elimination will occur after β-elimination which completely removes the abasic site leaving a 3'-P on the upstream fragment and a 5'-P on the downstream fragment | * Under strong alkaline conditions, δ-elimination will occur after β-elimination which completely removes the abasic site leaving a 3'-P on the upstream fragment and a 5'-P on the downstream fragment | ||
* Amines (such as amino acids or polyamines like putrescine, spermidiine, and spermine) greatly increase the rate of strand breakage at abasic sites | |||
==References== | ==References== | ||
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#frederico93 pmid=8329382 | #frederico93 pmid=8329382 | ||
#lindahl72 pmid=4626532 | #lindahl72 pmid=4626532 | ||
#lindahl72b pmid=4559796 | |||
</biblio> | </biblio> | ||
