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In this work, the possibility of constructing a thermo-switchable enzyme according to the 'molecular gate' strategy is demonstrated. The approach is based on the covalent attachment of oligodeoxyribonucleotides to cysteine residues of an enzyme adjacent to its active center to form a temporal barrier for enzyme-substrate complex formation. The activity of the modified enzyme that had been studied here-the restriction endonuclease SsoII (R.SsoII)-was diminished by a factor of 180 at 25 °С that almost abolished the enzymatic activity when compared with the unmodified enzyme. However, heating of the modified enzyme to 45 °С resulted in a 30-fold increase of activity. The activity of unmodified R.SsoII also increased on heating from 25 to 45 °; however, the difference did not exceed a factor of 3-4. The changes in enzymatic activity observed were shown to be reversible for both the unmodified and the modified R.SsoII. Variation of the length and the sequence of the attached oligodeoxyribonucleotides might allow greater modulation of the activity of DNA-protein conjugates. © 2013 IUBMB Life, 65(12):1012-1016, 2013 [ABSTRACT FROM AUTHOR]

Modified oligonucleotides bearing 2′-reactive groups or 2′-conjugated molecules have found wide application as structural tools in molecular biology. Of principal interest has been the use of 2′-reactive oligonucleotides for cross-linking with biomolecules and of 2′-conjugated oligonucleotides in hybridization assays. In this review we compare a range of electrophilic, nucleophilic and photoreactive groups for cross-linking and conjugation studies. IUBMB Life, 56: 209-214, 2004 [ABSTRACT FROM AUTHOR]

The double-stranded oligodeoxyribonucleotides with single internucleotide disulfide linkages were successfully used for covalent trapping of cysteine containing protein. In particular, an efficient conjugation of DNA methyltransferase SsoII to sequence-specific decoys was demonstrated. The obtained results assume that synthetic oligodeoxyribonucleotides bearing a new trapping site can be used as new tools to study and manipulate biological systems. [Copyright &y& Elsevier]