1xci
From Proteopedia
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Mispair Aligned N3T-Butyl-N3T Interstrand Crosslink
Overview
The introduction of a covalent interstrand cross-link induces changes in, the intrinsic structure and deformability of the DNA helix that are, recognized by elements of the DNA repair apparatus. In this context, the, solution structure of the undecamer d(CGAAAT*TTTCG)2, where T* represents, a N3T-butyl-N3T interstrand cross-link, was determined using molecular, dynamics calculations restrained by NOE and dihedral angle data obtained, from NMR spectroscopy. The structure of this cross-linked undecamer shows, dramatic widening of the major groove of the B-DNA stem without disruption, of Watson-Crick base pairing. This change in tertiary structure, illustrates the cumulative effect of cooperativity in intrastrand base, stacking of an A-tract of three adenines. Further, it is the direct result, from the imposition of geometric angular constraints by the cross-link, chain on an ApT* and T*pT steps in the segment AAAT*T. The widening of the, major groove is due to the dominant contribution of base stacking to the, stability of the ApT compared to the TpT step suggesting that the latter, is more deformable within a DNA stem. Compared to earlier structures of, ethyl cross-linked oligonucleotides, this unique perturbation induced by, the butyl moiety offers a new probe for systematic studies of DNA repair, mechanisms.
About this Structure
1XCI is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Intrastrand base-stacking buttresses widening of major groove in interstrand cross-linked B-DNA., da Silva MW, Bierbryer RG, Wilds CJ, Noronha AM, Colvin OM, Miller PS, Gamcsik MP, Bioorg Med Chem. 2005 Jul 15;13(14):4580-7. PMID:15953553
Page seeded by OCA on Sun Nov 25 01:51:39 2007
