[Study of the substrate-induced changes in the state of Eco dam methylase using a method of small-angle x-ray scattering].

Interaction of Ecodam methylase (E.C. 2.1.1) with synthetic oligonucleotide substrates of various primary structure was studied by the small angle X-ray scattering method. Complex formation between the enzyme and substrates occurs after addition of double-stranded oligonucleotides to the methylase. In the presence of 1 M NaC1 (when the enzyme is inactive) addition of the synthetic substrates does not result in complex formation. Comparison of the experimental scattering parameters with the calculated ones has been made. The best coincidence of these data is obtained for the model which proposed Ecodam methylase dimer formation in the course of its interaction with the substrates.