Wheat Endonuclease WEN1 Dependent on S-Adenosyl-L-Methionine and Sensitive to DNA Methylation Status

Abstract

Ca²⁺-, Mg²⁺-dependent wheat endonuclease WEN1 with molecular mass of about 27 kDa was isolated from coleoptyles. Methylated DNA of λ phage grown on E. coli dam⁺, dcm⁺ cells was hydrolyzed by WEN1 more effectively than DNA of phage grown on dam , dcm- cells. Two pH activity maxima (pH 6.5-7.5 and 9.0-10.5) were observed when double-stranded DNA was hydrolyzed. WEN1 is stable at elevated temperatures (65оС) and in wide range of pH values. WEN1 is activated by S-adenosyl-L-methionine, S-adenosyl-L-homocysteine and S-izobutyladenosine. It is a first case to show that higher eukaryote endonuclease discriminates between DNA of various methylation status and is modulated by S-AdoMet and its analogs.