456d

MOLECULAR AND CRYSTAL STRUCTURE OF D(CGCGMO6AATCCGCG): THE WATSON-CRICK TYPE N6-METHOXYADENOSINE/CYTIDINE BASE-PAIRS IN B-DNA

spinqualitylabelsall models 456d, resolution 1.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 456d is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MG NonStd Res: A47 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Oxyamines such as hydroxylamine and methoxylamine disturb DNA replication and act as potent mutagens, causing nucleotide transition from one purine to another or one pyrimidine to another. In order to investigate mismatch base-pairing in DNA damaged with oxyamines, a dodecamer with the sequence d(CGCGmo(6)AATCCGCG), where mo(6) A is 2'-deoxy-N(6)-methoxyadenosine, was synthesized and its crystal structure determined. No significant conformational changes are found between the present dodecamer and the original undamaged B-form dodecamer. Electron density maps clearly show that the mo(6)A residue forms a base-pair with a 2'-deoxycytidine residue through hydrogen bonds similar to a Watson-Crick G.C base-pair. For these hydrogen bonds to be made, N(6)-methoxyadenine must chemically take the imino form. The methoxylation thus enables the adenine base to mimic a guanine base. As a result, misincorporation of 2'-deoxycytidine instead of thymidine, or 2'-deoxyadenosine instead of 2'-deoxyguanosine, can occur in DNA replication. Crystallographic studies on damaged DNAs. I. An N(6)-methoxyadenine residue forms a Watson-Crick pair with a cytosine residue in a B-DNA duplex.,Chatake T, Ono A, Ueno Y, Matsuda A, Takenaka A J Mol Biol. 1999 Dec 17;294(5):1215-22. PMID:10600379 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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