Team:Imperial College London/M3/Genetic/DpnTaq

DpnII

DpnII comes from Streptococccus Pneumonia.

Cells of Streptococccus Pneumonia contain either DpnII, or the more well-known DpnI as part of their restriction machinery. Both recognise the same sequence of GATC and cleave before G. However, DpnII only acts on the unmethylated strand, as opposed to DpnI that only cleaves methylated strands.

The DpnII restriction cassette contains 2 methylases and 1 endonuclease.

TaqI

TaqI comes from the thermophile thermus aquaticus.

TaqI recognises the sequence TCGA and cleaves after T.

Interestingly, the TaqI gene contains 7 TaqI sites, probably important in regulating restriction endonuclease expression.

The TaqI restriction cassette contains 1 methylase and 1 endonuclease.

References