| Autor: |
Riazanova AIu, Molochkov NV, Abrosimova LA, Alekseevskiĭ AV, Kariagina AS, Protsenko AS, Friedhoff P, Oretskaia TS, Kubareva EA |
| Jazyk: |
ruština |
| Zdroj: |
Molekuliarnaia biologiia [Mol Biol (Mosk)] 2010 Sep-Oct; Vol. 44 (5), pp. 911-21. |
| Abstrakt: |
(Cytosine-5)-DNA methyltransferase SsoII (M.SsoII) has a long N-terminal region (1-71 residues) preceding the sequence with conservative motifs, which are characteristic for all DNA methyltransferases of such kind. The presence of this region provides M.SsoII capability to act as a transcription regulator in SsoII restriction-modification system. To perform its regulatory function, M.SsoII binds specifically to a 15-mer inverted repeat in the promoter region of SsoII restriction-modification system genes. In the present work, properties of the protein delta(72-379)M.Ecl18kI are studied, which is a deletion mutant of the SsoII-like DNA-methyltransferase M.Ecl18kI and is homologous to M.SsoII N-terminal region. delta(72-379)M.Ecl18kI capability to bind specifically a DNA duplex containing the regulatory site is demonstrated. However, such a binding takes place only in the presence of high protein excess relative to DNA, which could indicate an altered structure in the deletion mutant in comparison with the full-length M.SsoII. Circular dichroism spectroscopy demonstrated that delta(72-379)M.Ecl18kI has a strongly pronounced secondary structure and contains 32% a-helices and 20% beta-sheets. Amino acid sequences alignment of M.SsoII N-terminal region and transcription factors of known spatial structure is made. An assumption is made how alpha-helices and beta-sheets are arranged in M.SsoII N-terminal region. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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