Isolation and Characterization of Site-Specific DNA-methyltransferases from Bacillus coagulans K

I. V. Svadbina¹, N. V. Zelinskaya², N. P. Kovalevskaya², L. A. Zheleznaya¹, and N. I. Matvienko^2*

¹Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia; fax: (0967) 79-0553

²Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russia; fax: (7-095) 924-0493; E-mail: nikmatv@vega.protres.ru

^* To whom correspondence should be addressed.

Received April 18, 2003; Revision received May 30, 2003

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Two site-specific DNA methyltransferases, M.BcoKIA and M.BcoKIB, were isolated from the thermophilic strain Bacillus coagulans K. Each of the methylases protects the recognition site 5´-CTCTTC-3´/5´-GAAGAG-3´ from cleavage with the cognate restriction endonuclease BcoKI. It is shown that M.BcoKIB is an N6-adenine specific methylase and M.BcoKIA is an N4-cytosine specific methylase. According to bisulfite mapping, M.BcoKIA methylates the first cytosine in the sequence 5´-CTCTTC-3´.

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KEY WORDS: DNA methyltransferase, IIS restriction endonuclease, bisulfite mapping, N4-methylcytosine, N6-methyladenine

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