Abstract

A new crystal form was obtained for the complex between (ACGTACGT)2 and echinomycin and X-ray data were collected to 1.6 A. The structure was phased by the SAD method based on a single unexpected anomalous scatterer that could be identified as a mixture of nickel and zinc by measurements of the anomalous scattering at different wavelengths. This cation is coordinated by two guanines from two different duplexes and four water molecules. The structure resembles previously reported crystal structures of DNA-echinomycin complexes, except that three of the eight base pairs flanking the echinomycin bisintercalator sites have the Watson-Crick rather than the Hoogsteen configuration. Hoogsteen binding was found for the corresponding base pairs of the crystallographically independent duplex, indicating that the two configurations are very close in energy.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.