1ana

<StructureSection load='1ana' size='340' side='right' caption='[[1ana]], [[Resolution|resolution]] 2.00&Aring;' scene=''>

<table><tr><td colspan='2'>[[1ana]] is a 2 chain structure. The November 2001 RCSB PDB [http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''DNA'' by David S. Goodsell is [http://dx.doi.org/10.2210/rcsb_pdb/mom_2001_11 10.2210/rcsb_pdb/mom_2001_11]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ANA OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1ANA FirstGlance]. <br>

</td></tr><tr><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=C38:5-IODO-2-DEOXY-CYTIDINE-5-MONOPHOSPHATE'>C38</scene></td></tr>

<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=1ana FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ana OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1ana RCSB], [http://www.ebi.ac.uk/pdbsum/1ana PDBsum]</span></td></tr>

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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.

 

Helix geometry and hydration in an A-DNA tetramer: IC-C-G-G.,Conner BN, Yoon C, Dickerson JL, Dickerson RE J Mol Biol. 1984 Apr 25;174(4):663-95. PMID:6726797<ref>PMID:6726797</ref>

 

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<references/>

[[Category: Conner, B N.]]

[[Category: Dickerson, J L.]]

[[Category: Dickerson, R E.]]

[[Category: Yoon, C.]]

[[Category: Modified]]