CLONING AND ANALYSIS OF BIOCHEMICAL AND CATALYTIC PROPERTIES OF DNA METHYLTRANSFERASE M1.BspACI
Genes coding for the DNA methyltransferases of restriction-modification system BspACI from Bacillus psychrodurans AC have been cloned in E. coli cells. The analysis of amino acid sequences of the proteins showed that both these genes belong to C5 DNA methyltransferases. Gene bspACIM1 has been subcloned in pJW2 vector. High-purity recombinant enzyme has been obtained with chromatography on different carriers. It has been shown that M1.BspACI modifies the first cytosine residue in the sequence 5ґ-CCGC-3ґ. Kinetic parameters have been determined. The catalytic constant appears to be 0,095 ± 0,002 min-1, Km ДНК фага l - 0,053 ± 0,007 мкМ, Km SAM - 5,1 ± 0,3 мкМ.