456d | pdb_0000456d
MOLECULAR AND CRYSTAL STRUCTURE OF D(CGCGMO6AATCCGCG): THE WATSON-CRICK TYPE N6-METHOXYADENOSINE/CYTIDINE BASE-PAIRS IN B-DNA
|
Overview
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.
About this Structure
456D is a Protein complex structure of sequences from [1] with MG as ligand. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Tue Jan 29 21:44:14 2008
