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Published February 2000 | public
Journal Article

Structure of a photoactive rhodium complex intercalated into DNA

Abstract

Intercalating complexes of rhodium(III) are strong photo-oxidants that promote DNA strand cleavage or electron transfer through the double helix. The 1.2 Å resolution crystal structure of a sequence-specific rhodium intercalator bound to a DNA helix provides a rationale for the sequence specificity of rhodium intercalators. It also explains how intercalation in the center of an oligonucleotide modifies DNA conformation. The rhodium complex intercalates via the major groove where specific contacts are formed with the edges of the bases at the target site. The phi ligand is deeply inserted into the DNA base pair stack. The primary conformational change of the DNA is a doubling of the rise per residue, with no change in sugar pucker from B-form DNA. Based upon the five crystallographically independent views of an intercalated DNA helix observed in this structure, the intercalator may be considered as an additional base pair with specific functional groups positioned in the major groove.

Additional Information

© 2000 Nature America Inc. Received 30 September, 1999; accepted 17 December, 1999. We are grateful to the NIH for research support and to the NSF and NIH for predoctoral fellowships to C.L.K and K.E.E. We thank L. Joshua-Tor, S.S. David, J.E. Wedekind, A.J. Chirino and R. Bau for assistance with the structure solution, and S. Horvath for oligonucleotide synthesis. The rotation camera facility at SSRL is supported by the U.S. Department of Energy and NIH.

Additional details

Created:
August 19, 2023
Modified:
October 19, 2023