112d

MOLECULAR STRUCTURE OF THE G.A BASE PAIR IN DNA AND ITS IMPLICATIONS FOR THE MECHANISM OF TRANSVERSION MUTATIONS

spinqualitylabelsall models 112d, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 112d is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The synthetic deoxydodecamer d(C-G-C-G-A-A-T-T-A-G-C-G) was analyzed by x-ray diffraction methods, and the structure was refined to a residual error of R = 0.17 at 2.5-A resolution (2 sigma data) with 83 water molecules located. The sequence crystallizes as a full turn of a B-DNA helix and contains 2 purine X purine (G.A) base pairs and 10 Watson-Crick base pairs. The analysis shows conclusively that adenine is in the syn orientation with respect to the sugar moiety whereas guanine adopts the usual trans orientation. Nitrogen atoms of both bases are involved in hydrogen bonding with the N-1 of guanine 2.84 A from the N-7 of adenine and the N-6 of adenine within 2.74 A of the O-6 of guanine. The C-1'...C-1' separation is 10.7 A close to that for standard Watson-Crick base pairs. The incorporation of the purine.purine base pairs at two steps in the dodecamer causes little perturbation of either the local or the global conformation of the double helix. Comparison of the structural features with those of the G.T wobble pair and the standard G.C pair suggests a rationale for the differential enzymatic repair of the two types of base-pair mismatches. Molecular structure of the G.A base pair in DNA and its implications for the mechanism of transversion mutations.,Brown T, Hunter WN, Kneale G, Kennard O Proc Natl Acad Sci U S A. 1986 Apr;83(8):2402-6. PMID:3458205 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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