2ANA

THE CRYSTAL STRUCTURE OF D(G-G-G-G-C-C-C-C). A MODEL FOR POLY(DG).POLY(DC)

Summary for 2ANA

• Entry DOI: 10.2210/pdb2ana/pdb
• Descriptor: DNA (5'-D(*GP*GP*GP*GP*CP*CP*CP*C)-3') (1 entity in total)
• Functional Keywords: a-dna, double helix, dna
• Total number of polymer chains: 2
• Total formula weight: 4857.19

Authors

McCall, M.,Brown, T.,Kennard, O. (deposition date: 1985-08-05, release date: 1985-08-05, Last modification date: 2024-02-14)

Primary citation

McCall, M.,Brown, T.,Kennard, O.
The crystal structure of d(G-G-G-G-C-C-C-C). A model for poly(dG).poly(dC).
J.Mol.Biol., 183:385-396, 1985

PubMed Abstract: The structure of the DNA oligomer d(G-G-G-G-C-C-C-C) has been determined at a resolution of 2.5 A by single-crystal X-ray methods. There are two strands in the asymmetric unit, and these coil about each other to form a right-handed double-helix of the A-type with Watson-Crick hydrogen bonds between base-pairs. The helix has a shallow minor groove and a deep, water-filled major groove; almost all exposed functional groups on the DNA are hydrated, and 106 ordered solvent molecules have been found. The two d(G-G-G-G).d(C-C-C-C) segments in the octamer exhibit similar and uniform structures, but there is a slight discontinuity at the GpC step between them. A recurring feature of the structure is the overlap of adjacent guanine bases in each GpG step, with the five-membered ring of one guanine stacking on the six-membered ring of its neighbour. There is little or no overlap between adjacent cytosine rings. Conformational parameters for these GpG steps are compared with those from other single-crystal X-ray analyses. In general, GpG steps exhibit high slide, low roll and variable twist. Models for poly(dG).poly(dC) were generated by applying a simple rotation and translation to each of the unmodified d(G-G-G-G).d(C-C-C-C) units. Detailed features of these models are shown to be compatible with various assays of poly(dG).poly(dC) in solution, and are useful in understanding the polymorphic behaviour of this sequence under a variety of experimental conditions.

PubMed: 4020865
DOI: 10.1016/0022-2836(85)90009-9

Experimental method

X-RAY DIFFRACTION (2.5 Å)