Cloning and expression of a new site-specific methyltransferase M.SscL1I from Staphylococcus sp L1

The gene of the new site-specific methyltransferase M.SscL1I belonging to t he same modification-restriction system as the previously described by us s ite-specific endonuclease SscL1I has been cloned from the natural strain St aphylococcus sp. L1. A plasmid to express the methylase gene under control of the T7 phage-specific promotor has been constructed. Conditions were fou nd to express the recombinant methylase M.SscL1I and to purify it to near h omogeneity. It is shown that the methylase modifies the adenine base in the recognition site 5'-GANTC-3'.