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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1984-7-11
|
| pubmed:abstractText |
The DNA oligomer of sequence IC-C-G-G has been synthesized, and its X-ray crystal structure solved at a resolution of 2.0 A, using anomalous scattering from iodines in phase analysis: 48 cycles of Jack-Levitt restrained least-squares refinement resulted in a residual error of 19.9% over all data, or 16.5% for two-sigma data. Two double-helical tetramers stack in the crystal to form a continuous octamer, except for the two missing phosphate connections across the center. The octamer has a mean helix rotation of 33.7 degrees (10.7 base-pairs per turn), rise of 2.87 A, mean inclination angle of base-pairs of 14 degrees, and mean base-pair propeller twist of +16.3 degrees. Local variations in both helix rotation and base plane roll angles, including those across the center of the octamer, are as predicted from base sequence by sum functions sigma 1 and sigma 2. The three known DNA octamers: IC-C-G-G/IC-C-G-G, G-G-T-A-T-A-C-C and G-G-C-C-G-G-C-C, make up a graded series in this order, with monotonically changing structural parameters. An exhaustive comparison of torsion angle correlations among the known A helices confirms some structural expectations and reveals some new features. 86 water molecules have been located per double-helical IC-C-G-G tetramer (the asymmetric unit), of which 451/2 per tetramer lie within a first hydrogen-bonded shell of hydration. No ordered water structure is observed comparable to the minor groove spine of hydration in B-DNA.
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| pubmed:grant | |
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0022-2836
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
25
|
| pubmed:volume |
174
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
663-95
|
| pubmed:dateRevised |
2007-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:6726797-Base Sequence,
pubmed-meshheading:6726797-Carbohydrate Conformation,
pubmed-meshheading:6726797-Crystallography,
pubmed-meshheading:6726797-DNA,
pubmed-meshheading:6726797-Models, Chemical,
pubmed-meshheading:6726797-Nucleic Acid Conformation,
pubmed-meshheading:6726797-Statistics as Topic
|
| pubmed:year |
1984
|
| pubmed:articleTitle |
Helix geometry and hydration in an A-DNA tetramer: IC-C-G-G.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
|