1UE4
Crystal structure of d(GCGAAAGC)
Summary for 1UE4
| Entry DOI | 10.2210/pdb1ue4/pdb |
| Related | 1UE2 1UE3 |
| Descriptor | 5'-D(*GP*CP*GP*AP*AP*AP*GP*C)-3', MAGNESIUM ION (3 entities in total) |
| Functional Keywords | dna, sheared g:a pair, bulge-in duplex, g:axa:g crossing |
| Total number of polymer chains | 1 |
| Total formula weight | 2484.95 |
| Authors | Sunami, T.,Kondo, J.,Hirao, I.,Watanabe, K.,Miura, K.,Takenaka, A. (deposition date: 2003-05-09, release date: 2004-03-09, Last modification date: 2023-10-25) |
| Primary citation | Sunami, T.,Kondo, J.,Hirao, I.,Watanabe, K.,Miura, K.,Takenaka, A. Structures of d(GCGAAGC) and d(GCGAAAGC) (tetragonal form): a switching of partners of the sheared G.A pairs to form a functional G.AxA.G crossing. Acta Crystallogr.,Sect.D, 60:422-431, 2004 Cited by PubMed Abstract: The DNA fragments d(GCGAAGC) and d(GCGAAAGC) are known to exhibit several extraordinary properties. Their crystal structures have been determined at 1.6 and 1.65 A resolution, respectively. Two heptamers aligned in an antiparallel fashion associate to form a duplex having molecular twofold symmetry. In the crystallographic asymmetric unit, there are three structurally identical duplexes. At both ends of each duplex, two Watson-Crick G.C pairs constitute the stem regions. In the central part, two sheared G.A pairs are crossed and stacked on each other, so that the stacked two guanine bases of the G.AxA.G crossing expose their Watson-Crick and major-groove sites into solvent, suggesting a functional role. The adenine moieties of the A(5) residues are inside the duplex, wedged between the A(4) and G(6) residues, but there are no partners for interactions. To close the open space on the counter strand, the duplex is strongly bent. In the asymmetric unit of the d(GCGAAAGC) crystal (tetragonal form), there is only one octamer chain. However, the two chains related by the crystallographic twofold symmetry associate to form an antiparallel duplex, similar to the base-intercalated duplex found in the hexagonal crystal form of the octamer. It is interesting to note that the significant difference between the present bulge-in structure of d(GCGAAGC) and the base-intercalated duplex of d(GCGAAAGC) can be ascribed to a switching of partners of the sheared G.A pairs. PubMed: 14993665DOI: 10.1107/S0907444903028415 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.65 Å) |
Structure validation
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