Structure and Dynamics of the Tetrameric Mnt Repressor and a Model for its DNA Complex
The tetrameric Mnt repressor of bacteriophage P22 consists of two dimeric DNA-binding domains and a tetramerization domain. The NOE and chemical shift data demonstrate that the structures of the domains in the wild-type repressor protein are similar to those of the separate domains, the three-dimens...
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Published in | Journal of biomolecular structure & dynamics Vol. 17; no. sup1; pp. 113 - 122 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
England
Taylor & Francis Group
01.01.2000
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Subjects | |
Online Access | Get full text |
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Summary: | The tetrameric Mnt repressor of bacteriophage P22 consists of two dimeric DNA-binding domains and a tetramerization domain. The NOE and chemical shift data demonstrate that the structures of the domains in the wild-type repressor protein are similar to those of the separate domains, the three-dimensional structures of which have been determined previously.
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N relaxation measurements show that the linker that connects the anti-parallel four-helix bundle with the two β-sheet DNA-binding dimers is highly flexible. No evidence was found for interactions between the distinct modules. The
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N relaxation properties of the two domains differ substantially, confirming their structural independence. A model in which one two-stranded coiled coil of the four-helix bundle is attached to one N-terminal dimer is most consistent with the biochemical data and
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N relaxation data. For the Mnt-DNA complex this geometry fits with a model in which the two β-sheet DNA-binding domains are bound at two successive major grooves of the Mnt operator and the tetramerization domain is packed between these two DNA-bound dimers. In such a model the two-fold symmetry axis of the four-helix bundle coincides with that of the operator sequence and the two bound dimers. Bending of the Mnt operator of approximately 30° upon binding of the tetramer, as measured by gel-shift assays, is in agreement with this model of the Mnt-DNA complex. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0739-1102 1538-0254 |
DOI: | 10.1080/07391102.2000.10506611 |