Ecori DNA methylase activity is eliminated upon histidine residue modification

• Published in: Biochemical and biophysical research communications Vol. 164; no. 1; pp. 233 - 237
• Main Authors: Everett, Elizabeth Ann, Reich, N.O.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 16.10.1989; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Chemical Phenomena; Chemistry; Diethyl Pyrocarbonate - pharmacology; Enzymes and enzyme inhibitors; Escherichia coli; Fundamental and applied biological sciences. Psychology; Histidine - metabolism; Site-Specific DNA-Methyltransferase (Adenine-Specific) - antagonists & inhibitors; Transferases; Enzyme
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(89)91707-5

The E.coli EcoRI DNA methylase activity is completely eliminated in five minutes upon incubation with the histidine residue specific reagent diethyl pyrocarbonate. In that two moles of N-ethoxyformylimidazole per mole of methylase are detected spectroscopically upon inactivation and activity is not restored by hydroxylamine, it is likely that activity loss is due to double modification of a single histidine residue. This information is critical in determining the enzymatic mechanism, causes of the pH-activity curve, designing protein mutants and interpreting previous structure-function data.