5ana: Difference between revisions
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[[ | ==THE CRYSTAL STRUCTURE OF D(GTACGTAC) AT 2.25 ANGSTROMS RESOLUTION. ARE THE A-DNA'S ALWAYS UNWOUND APPROXIMATELY 10 DEGREES AT THE C-G STEPS== | ||
<StructureSection load='5ana' size='340' side='right' caption='[[5ana]], [[Resolution|resolution]] 2.25Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[5ana]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5ANA OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5ANA FirstGlance]. <br> | |||
</td></tr><tr><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene><br> | |||
<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5ana FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ana OCA], [http://www.rcsb.org/pdb/explore.do?structureId=5ana RCSB], [http://www.ebi.ac.uk/pdbsum/5ana PDBsum]</span></td></tr> | |||
<table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The structure of the self-complementary octamer d(GTACGTAC) has been analyzed by a single crystal X-ray diffraction method at 2.25 A resolution. The crystallographic R factor was 0.184 for all 1233 reflections at this resolution. In spite of the alternating purine-pyrimidine sequence, d(GTACGTAC) adopts the A-form conformation rather than the left-handed Z-form. The average helix twist and the mean rise per base pair are 32.1 degrees and 3.18 A, respectively. The d(GTACGTAC) helix is characterized by a wide open major groove and small base-pair tilt (9.7 degrees). The partial unwinding of the helix is observed only at the central pyrimidine-purine C-G step, but not at the other pyrimidine-purine T-A steps. Based on this study and six other X-ray studies, we propose a hypothesis that the A-DNA's are always unwound approximately 10 degrees at the C-G steps. Significant differences in base-pair stacking modes are seen between the purine-pyrimidine step and the pyrimidine-purine step. All deoxyribose rings adopt the C3'-endo conformation. All backbone torsion angles fall into the range expected for the A-DNA form, except for the nucleotide G5, whose alpha and gamma torsion angles adopt the trans, trans conformation instead of the common gauche-, gauche+ conformation. | |||
The crystal structure of d(GTACGTAC) at 2.25 A resolution: are the A-DNA's always unwound approximately 10 degrees at the C-G steps?,Takusagawa F J Biomol Struct Dyn. 1990 Feb;7(4):795-809. PMID:2310515<ref>PMID:2310515</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
< | |||
[[Category: Takusagawa, F.]] | [[Category: Takusagawa, F.]] | ||
[[Category: A-dna]] | [[Category: A-dna]] | ||
[[Category: Dna]] | [[Category: Dna]] | ||
[[Category: Double helix]] | [[Category: Double helix]] | ||
Revision as of 10:26, 16 June 2014
THE CRYSTAL STRUCTURE OF D(GTACGTAC) AT 2.25 ANGSTROMS RESOLUTION. ARE THE A-DNA'S ALWAYS UNWOUND APPROXIMATELY 10 DEGREES AT THE C-G STEPS
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