1zyg
From Proteopedia
(New page: 200px<br /><applet load="1zyg" size="350" color="white" frame="true" align="right" spinBox="true" caption="1zyg" /> '''Structure of a Supercoiling Responsive DNA S...) |
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==Overview== | ==Overview== | ||
| - | In both eukaryotes and prokaryotes, negative supercoiling of chromosomal | + | In both eukaryotes and prokaryotes, negative supercoiling of chromosomal DNA acts locally to regulate a variety of cellular processes, such as transcription, replication, recombination and response to environmental stresses. While studying the interaction between the Hin recombinase and mutated versions of its cognate DNA-binding site, we identified a mutated DNA site that binds Hin only when the DNA is supercoiled. To understand the mechanism of this supercoiling-responsive DNA site, we used NMR spectroscopy and fluorescence resonance energy transfer to determine the solution structures and dynamics of three related DNA oligonucleotides. The supercoiling-responsive DNA site formed a partially unwound and stretched helix and showed significant flexibility and base pair opening kinetics. The single CAG/CTG triplet contained in this DNA sequence displayed the same characteristics as do multiple CAG/CTG repeats, which are associated with several hereditary neuromuscular diseases. It is known that short DNA sequence motifs that have either very high or low bending flexibility occur preferentially at supercoiling-sensitive bacterial and eukaryotic promoters. From our results and these previous data, we propose a model in which supercoiling utilizes the intrinsic flexibility of a short DNA site to switch the local DNA structure from an inefficient conformation for protein binding to an efficient one, or vice versa. |
==About this Structure== | ==About this Structure== | ||
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Structural and dynamic basis of a supercoiling-responsive DNA element., Bae SH, Yun SH, Sun D, Lim HM, Choi BS, Nucleic Acids Res. 2006 Jan 9;34(1):254-61. Print 2006. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16414956 16414956] | Structural and dynamic basis of a supercoiling-responsive DNA element., Bae SH, Yun SH, Sun D, Lim HM, Choi BS, Nucleic Acids Res. 2006 Jan 9;34(1):254-61. Print 2006. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16414956 16414956] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Bae, S | + | [[Category: Bae, S H.]] |
| - | [[Category: Choi, B | + | [[Category: Choi, B S.]] |
| - | [[Category: Lim, H | + | [[Category: Lim, H M.]] |
[[Category: Sun, D.]] | [[Category: Sun, D.]] | ||
| - | [[Category: Yun, S | + | [[Category: Yun, S H.]] |
[[Category: dna]] | [[Category: dna]] | ||
[[Category: hin]] | [[Category: hin]] | ||
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[[Category: supercoiling]] | [[Category: supercoiling]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:20:17 2008'' |
Revision as of 14:20, 21 February 2008
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Structure of a Supercoiling Responsive DNA Site
Overview
In both eukaryotes and prokaryotes, negative supercoiling of chromosomal DNA acts locally to regulate a variety of cellular processes, such as transcription, replication, recombination and response to environmental stresses. While studying the interaction between the Hin recombinase and mutated versions of its cognate DNA-binding site, we identified a mutated DNA site that binds Hin only when the DNA is supercoiled. To understand the mechanism of this supercoiling-responsive DNA site, we used NMR spectroscopy and fluorescence resonance energy transfer to determine the solution structures and dynamics of three related DNA oligonucleotides. The supercoiling-responsive DNA site formed a partially unwound and stretched helix and showed significant flexibility and base pair opening kinetics. The single CAG/CTG triplet contained in this DNA sequence displayed the same characteristics as do multiple CAG/CTG repeats, which are associated with several hereditary neuromuscular diseases. It is known that short DNA sequence motifs that have either very high or low bending flexibility occur preferentially at supercoiling-sensitive bacterial and eukaryotic promoters. From our results and these previous data, we propose a model in which supercoiling utilizes the intrinsic flexibility of a short DNA site to switch the local DNA structure from an inefficient conformation for protein binding to an efficient one, or vice versa.
About this Structure
1ZYG is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Structural and dynamic basis of a supercoiling-responsive DNA element., Bae SH, Yun SH, Sun D, Lim HM, Choi BS, Nucleic Acids Res. 2006 Jan 9;34(1):254-61. Print 2006. PMID:16414956
Page seeded by OCA on Thu Feb 21 16:20:17 2008
Categories: Protein complex | Bae, S H. | Choi, B S. | Lim, H M. | Sun, D. | Yun, S H. | Dna | Hin | Hix | Recombinase | Supercoiling
