Secondary structure of SsoII-like (Cytosine-5)-DNA methyltransferases N-terminal region determined by Circular dichroism spectroscopy
(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 methyltrans-ferases of such kind. The presence of this region provides M.SsoII capability to act as a transcription re...
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Published in | Molecular biology (New York) Vol. 44; no. 5; pp. 807 - 816 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Dordrecht
Dordrecht : SP MAIK Nauka/Interperiodica
01.10.2010
SP MAIK Nauka/Interperiodica Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | (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 methyltrans-ferases 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 Δ(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. Δ(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 Δ(72-379)M.Ecl18kI has a strongly pronounced secondary structure and contains 32% α-helices and 20% β-strands. Amino acid sequences alignment of M.SsoII N-terminal region and transcription factors of known spatial structure is made. An assumption is made how α-helices and β-strands are arranged in M.SsoII N-terminal region. |
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Bibliography: | http://dx.doi.org/10.1134/S0026893310050183 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0026-8933 1608-3245 |
DOI: | 10.1134/S0026893310050183 |