Book of Abstracts: Albany 2003

category image Albany 2003
Conversation 13
Abstract Book
June 17-21 2003

Complexes of Cisplatin with d(CCTGGTCC)·d(GGACCAGG) and d(CCTCTGGTCTCC)·d(GGAGACCAGAGG) by VCD and IR

The structures of the complexes of cisplatin with both title oligomers in aqueous solution have been determined authoritatively by NMR (1,2). Compared to NMR, vibrational circular dichroism (VCD) is a relatively new spectroscopic technique, which has not yet been applied sufficiently frequently to authenticate changes of DNA structure in response to various agents in order to become universally accepted as a viable spectroscopic tool for this purpose. In the meantime, we used VCD very successfully as a complementary technique, which often is superior to infrared absorption for extracting structural information for DNA complexes with Mn2+, Cu2+, and Cr3+ ions (3,4). The goal of this investigation, therefore, was to test the capabilities of VCD on cisplatin complexes initially with selected synthetic oligonucleotides for which structural information was available for comparison.

The VCD spectra of both title oligomers when complexed with cis-platin in aqueous solution showed distinctive and characteristic changes in exquisite detail compared to infrared absorption. We were able to explain these changes in terms of the structural information deduced by NMR. VCD features were particularly informative for the platination site where the normal stacking of the base pairs is severely disrupted by the formation of the complex between the platinum atom and adjacent guanines in the oligomers.

Dimiter Tsankov1
Berndt Kalisch2
Hans van de Sande2
Valery Andrushchenko3
Hal Wieser3

1Institute of Organic Chemistry
Bulgarian Academy of Sciences
1113 Sofia, Bulgaria
2Department of Biochemistry and Molecular Biology
Faculty of Medicine
University of Calgary
3330 Hospital Drive N.W.
Calgary, AB
T2N 1N4, Canada
3Faculty of Science
University of Calgary
2500 University Dr. NW
Calgary, AB
T2N 1N4, Canada

References and Footnotes
  1. D. Yang, S. S. G. E. van Boom, J. Reedijk, J. H. van Boom, and A. H.-J. Wang, Biochem. 34, 12912-12921 (1995).
  2. A. Gelasco and S. J. Lippard, Biochem. 37, 9230-9239 (1998).
  3. V. Andrushchenko, J. H. van de Sande, and H. Wieser, Biopolymers, in press.
  4. V. Andrushchenko, J. H. van de Sande, and H. Wieser, Biospectroscopy, in press.
  5. V. Andrushchenko, Z. Leonenko, H. van de Sande, and H. Wieser, Biopolymers 61, 234-260 (2002).