1MP7 image
Deposition Date 2002-09-11
Release Date 2003-02-18
Last Version Date 2024-05-22
Entry Detail
PDB ID:
1MP7
Keywords:
Title:
A Third Complex of Post-Activated Neocarzinostatin Chromophore with DNA. Bulge DNA Binding from the Minor Groove
Biological Source:
Source Organism:
(Taxon ID: ) (Taxon ID: )
Method Details:
Experimental Method:
Conformers Calculated:
9
Conformers Submitted:
9
Selection Criteria:
all calculated structures submitted, back calculated data agree with experimental NOESY spectrum, structures with acceptable covalent geometry, structures with favorable non-bond energy, structures with the least restraint violations, structures with the lowest energy
Macromolecular Entities
Polymer Type:polydeoxyribonucleotide
Molecule:5'-D(*GP*CP*CP*AP*GP*AP*GP*AP*GP*C)-3'
Chain IDs:A
Chain Length:10
Number of Molecules:1
Biological Source:
Ligand Molecules
Primary Citation
New Complex of Post-Activated Neocarzinostatin Chromophore with DNA: Bulge DNA Binding from the Minor Groove
Biochemistry 42 1186 1198 (2003)
PMID: 12564921 DOI: 10.1021/bi0206210

Abstact

Neocarzinostatin (NCS-chrom), a natural enediyne antitumor antibiotic, undergoes either thiol-dependent or thiol-independent activation, resulting in distinctly different DNA cleavage patterns. Structures of two different post-activated NCS-chrom complexes with DNA have been reported, revealing strikingly different binding modes that can be directly related to the specificity of DNA chain cleavage caused by NCS-chrom. The third structure described herein is based on recent studies demonstrating that glutathione (GSH) activated NCS-chrom efficiently cleaves DNA at specific single-base sites in sequences containing a putative single-base bulge. In this structure, the GSH post-activated NCS-chrom (NCSi-glu) binds to a decamer DNA, d(GCCAGAGAGC), from the minor groove. This binding triggers a conformational switch in DNA from a loose duplex in the free form to a single-strand, tightly folded hairpin containing a bulge adenosine embedded between a three base pair stem. The naphthoate aromatic moiety of NCSi-glu intercalates into a GG step flanked by the bulge site, and its substituent groups, the 2-N-methylfucosamine carbohydrate ring and the tetrahydroindacene, form a complementary minor groove binding surface, mostly interacting with the GCC strand in the duplex stem of DNA. The bulge site is stabilized by the interactions involving NCSi-glu naphthoate and GSH tripeptide. The positioning of NCSi-glu is such that only single-chain cleavage via hydrogen abstraction at the 5'-position of the third base C (which is opposite to the putative bulge base) in GCC is possible, explaining the observed single-base cleavage specificity. The reported structure of the NCSi-glu-bulge DNA complex reveals a third binding mode of the antibiotic and represents a new family of minor groove bulge DNA recognition structures. We predict analogue structures of NCSi-R (R = glu or other substituent groups) may be versatile probes for detecting the existence of various structures of nucleic acids. The NMR structure of this complex, in combination with the previously reported NCSi-gb-bulge DNA complex, offers models for specific recognition of DNA bulges of various sizes through binding to either the minor or the major groove and for single-chain cleavage of bulge DNA sequences.

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