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SOLUTION NMR STRUCTURE OF SELF-COMPLIMENTARY DUPLEX 5'-D(TCCG*CGGA)2 CONTAINING A TRIMETHYLENE CROSSLINK AT THE N2 POSITION OF G*SOLUTION NMR STRUCTURE OF SELF-COMPLIMENTARY DUPLEX 5'-D(TCCG*CGGA)2 CONTAINING A TRIMETHYLENE CROSSLINK AT THE N2 POSITION OF G*
Structural highlights
Publication Abstract from PubMedMalondialdehyde interstrand cross-links in DNA show strong preference for 5'-d(CpG) sequences. The cross-links are unstable and a trimethylene cross-link has been used as a surrogate for structural studies. A previous structural study of the 5'-d(CpG) cross-link in the sequence 5'-d(AGGCGCCT), where G is the modified nucleotide, by NMR spectroscopy and molecular dynamics using a simulated annealing protocol showed the guanine residues and the tether lay approximately in a plane such that the trimethylene tether and probably the malondialdehyde tether, as well, could be accommodated without major disruptions of duplex structure [Dooley et al. J. Am Chem. Soc. 2001, 123, 1730-1739]. The trimethylene cross-link has now been studied in a GpC motif using the reverse sequence. The structure lacks the planarity seen with the 5'-d(CpG) sequence and is skewed about the trimethylene cross-link. Melting studies indicate that the trimethylene cross-link is thermodynamically less stable in the GpC motif than in the 5-d(CpG). Furthermore, lack of planarity of the GpC cross-link precludes making an isosteric replacement of the trimethylene tether by malondialdehyde. A similar argument can be used to explain the 5'-d(CpG) preference for interchain cross-linking by acrolein. NMR determination of the conformation of a trimethylene interstrand cross-link in an oligodeoxynucleotide duplex containing a 5'-d(GpC) motif.,Dooley PA, Zhang M, Korbel GA, Nechev LV, Harris CM, Stone MP, Harris TM J Am Chem Soc. 2003 Jan 8;125(1):62-72. PMID:12515507[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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