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 <i>Bacillus psychrodurans</i> AC have been cloned in <i>E. coli </i>cells. The analysis of amino acid sequences of the proteins showed that both these genes belong to C5 DNA methyltransferases. Gene <i>bspACIM1</i> 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<sup>-1</sup>, <i>K</i><sub><i></i>m</sub> <sub>ДНК фага l</sub> - 0,053 ± 0,007 мкМ,<i> K</i><sub><i></i>m SAM</sub> - 5,1 ± 0,3 мкМ.