|nick translation||medical dictionary|
E. coli DNA polymerase I will add a nucleotide, copying the complementary strand, to the free 3' OH group at a nick, at the same time its exonuclease activity removes the 5' terminus. The enzyme then adds a nucleotide at the new 3' OH and removes the new 5' terminus. In this way one strand of the DNA is replaced starting at a nick, which effectively moves along the strand. Nick translation refers to this translation or movement and not to protein synthesis.
In practice, DNA is mixed with trace amounts of DNAase I to generate nicks, DNA polymerase I and labelled nucleotides. Because the nicks are generated randomly the DNA preparation can be uniformly labelled and to a high degree of specific activity.
(10 Jan 1998)
|Bookmark with:||word visualiser||Go and visit our forums|