2l2v

NMR Solution Structures of -3 (3' staggered) Bistranded Abasic Site Lesions in DNA

spinqualitylabelsall models 2l2v, 4 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2l2v is a 2 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: 3DR Related: 1ycw, 1yct Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Publication Abstract from PubMed Ionizing radiation produces a distinctive pattern of bistranded clustered lesions in DNA. A relatively low number of clustered lesions may be lethal to cells when compared to a larger number of single lesions. Enzyme cleavage experiments suggest that the orientation of bistranded lesions causes differential recognition and removal of these lesions. Like that of a previous study of bistranded abasic site lesion [Hazel, R. D., Tian, K., and de los Santos, C. (2008) Biochemistry 47, 11909-11919], the aim of this investigation was to determine the structures of two DNA duplexes each containing two synthetic apurinic/apyrimidinic (AP) residues, positioned on opposite strands and separated by two base pairs. In the first duplex, the AP residues are staggered in the 3' orientation [-3 duplex, (AP)(2)-3 duplex], while in the second duplex, the AP residues are staggered in the 5' orientation [+3 duplex, (AP)(2)+3 duplex]. NOESY spectra recorded in 100 and 10% D(2)O buffer solutions allowed the assignment of the nonexchangeable and exchangeable protons, respectively, for each duplex. Cross-peak connectivity in the nonexchangeable proton spectra indicates that the duplex is a regular right-handed helix with the AP residues and orphan bases located inside the duplexes. The exchangeable proton spectra establish the formation of Watson-Crick G.C alignment for the two base pairs between the lesion sites in both duplexes. Distance-restrained molecular dynamics simulation confirmed the intrahelical orientations of the AP residues. The proximity of the AP residues across the minor groove of the -3 duplex and across the major groove in the +3 duplex is similar to their locations in the case of -1 and +1 clusters. This difference in structure may be a key factor in the differential recognition of bistranded AP lesions by human AP endonuclease. NMR solution structures of clustered abasic site lesions in DNA: structural differences between 3'-staggered (-3) and 5'-staggered (+3) bistranded lesions.,Hazel RD, de los Santos C Biochemistry. 2010 Oct 19;49(41):8978-87. PMID:20825249 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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