Activation of mammalian DNA methyltransferase by cleavage of a Zn binding regulatory domain.

摘要: Mammalian DNA (cytosine-5) methyltransferase contains a C-terminal domain that is closely related to bacterial cytosine-5 restriction methyltransferase. This linked large N-terminal domain. It shown here the Zn binding site and N- domains can be separated by cleavage with trypsin or Staphylococcus aureus protease V8; V8 was determined Edman degradation lie 10 residues of run alternating lysyl glycyl which joins two six first sequence motif conserved between mammalian cytosine methyltransferases. While intact enzyme had little activity on unmethylated substrates, caused stimulation initial velocity methylation without substantial change in rate hemimethylated DNA. These findings indicate ensures clonal propagation patterns through inhibition de novo likely have arisen via fusion prokaryotic-like an unrelated protein. Stimulation proteolytic vivo may contribute process ectopic observed aging animals, tumors lines cultured cells.