131d
From Proteopedia
(New page: 200px<br /><applet load="131d" size="450" color="white" frame="true" align="right" spinBox="true" caption="131d, resolution 1.000Å" /> '''THE LOW-TEMPERATURE...) |
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| - | [[Image:131d.jpg|left|200px]]<br /><applet load="131d" size=" | + | [[Image:131d.jpg|left|200px]]<br /><applet load="131d" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="131d, resolution 1.000Å" /> | caption="131d, resolution 1.000Å" /> | ||
'''THE LOW-TEMPERATURE CRYSTAL STRUCTURE OF THE PURE-SPERMINE FORM OF Z-DNA REVEALS BINDING OF A SPERMINE MOLECULE IN THE MINOR GROOVE'''<br /> | '''THE LOW-TEMPERATURE CRYSTAL STRUCTURE OF THE PURE-SPERMINE FORM OF Z-DNA REVEALS BINDING OF A SPERMINE MOLECULE IN THE MINOR GROOVE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The X-ray crystal structure of the pure-spermine form of the left-handed | + | The X-ray crystal structure of the pure-spermine form of the left-handed Z-DNA duplex [d(CGCGCG)]2 has been determined at a temperature of -110 degrees C. Whereas the previously described room temperature structure of the pure-spermine form showed only the presence of a single "interhelix" spermine molecule, mediating contacts between neighboring duplexes (Egli et al., 1991), a second "intrahelix" spermine molecule as well as two hydrated sodium ions were found in the structure determined at low temperature. This second spermine molecule binds primarily within the minor groove of two hexamer duplexes that are stacked in an end-to-end fashion in the crystal lattice. Thus, the intrahelix spermine molecule interacts with a single infinite helix. The spine of hydration observed in other structures of Z-DNA hexamers is partially replaced and partially displaced by the intrahelix spermine molecule. In Z-DNA, phosphate groups are relatively closely spaced across the minor groove compared to the right-handed double-helical conformation of B-DNA. The intrahelix spermine molecule decreases cross-groove electrostatic repulsion within the Z-DNA helix, thereby increasing its relative stability. This structure may therefore provide an explanation for the role of spermine as a very effective inducer of the conformational B-DNA to Z-DNA transition with alternating dG-dC sequences in solution. |
==About this Structure== | ==About this Structure== | ||
| - | 131D is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with SPM and NA as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 131D is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=SPM:'>SPM</scene> and <scene name='pdbligand=NA:'>NA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=131D OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Egli, M.]] | [[Category: Egli, M.]] | ||
[[Category: Rich, A.]] | [[Category: Rich, A.]] | ||
| - | [[Category: Williams, L | + | [[Category: Williams, L D.]] |
[[Category: NA]] | [[Category: NA]] | ||
[[Category: SPM]] | [[Category: SPM]] | ||
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[[Category: z-dna]] | [[Category: z-dna]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:37:59 2008'' |
Revision as of 09:38, 21 February 2008
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THE LOW-TEMPERATURE CRYSTAL STRUCTURE OF THE PURE-SPERMINE FORM OF Z-DNA REVEALS BINDING OF A SPERMINE MOLECULE IN THE MINOR GROOVE
Overview
The X-ray crystal structure of the pure-spermine form of the left-handed Z-DNA duplex [d(CGCGCG)]2 has been determined at a temperature of -110 degrees C. Whereas the previously described room temperature structure of the pure-spermine form showed only the presence of a single "interhelix" spermine molecule, mediating contacts between neighboring duplexes (Egli et al., 1991), a second "intrahelix" spermine molecule as well as two hydrated sodium ions were found in the structure determined at low temperature. This second spermine molecule binds primarily within the minor groove of two hexamer duplexes that are stacked in an end-to-end fashion in the crystal lattice. Thus, the intrahelix spermine molecule interacts with a single infinite helix. The spine of hydration observed in other structures of Z-DNA hexamers is partially replaced and partially displaced by the intrahelix spermine molecule. In Z-DNA, phosphate groups are relatively closely spaced across the minor groove compared to the right-handed double-helical conformation of B-DNA. The intrahelix spermine molecule decreases cross-groove electrostatic repulsion within the Z-DNA helix, thereby increasing its relative stability. This structure may therefore provide an explanation for the role of spermine as a very effective inducer of the conformational B-DNA to Z-DNA transition with alternating dG-dC sequences in solution.
About this Structure
131D is a Protein complex structure of sequences from [1] with and as ligands. Full crystallographic information is available from OCA.
Reference
The low-temperature crystal structure of the pure-spermine form of Z-DNA reveals binding of a spermine molecule in the minor groove., Bancroft D, Williams LD, Rich A, Egli M, Biochemistry. 1994 Feb 8;33(5):1073-86. PMID:8110738
Page seeded by OCA on Thu Feb 21 11:37:59 2008
Categories: Protein complex | Bancroft, D. | Egli, M. | Rich, A. | Williams, L D. | NA | SPM | Double helix | Z-dna
