Bis-intercalation (crosslinking) of DNA by an acridine-4-carboxamide скачать в хорошем качестве

Bis-intercalation (crosslinking) of DNA by an acridine-4-carboxamide

An example of the subtlety of intercalation modes. The ligand is a bis-acridine-4-carboxamide originally designed by Bill Denny. The C6 linker is too short for standard bis-intercalation to be an option, but not too short to link adjacent strands of the short hexamer duplex d(CGTACG)2. Interestingly, this is a beautifully ordered structure, showing the carboxamide sidechains differently oriented at the two end of the duplex. The CG/CG intercalation cavity gives a choise of the two guanines for H-bonding in the major groove, and both are observed. The twofold axes between the duplexes create two twofold symmetric, but different, overall conformations of the ligand. The linker is therefore in the minor groove side, linking two duplexes. The same C6 bis-acridine was shown by us to semi-insert into the Holliday junction structure, PDB: 2GWA.    • Intercalation into the DNA Holliday juncti...   A rendering of PDB entry 2GB9 'd(CGTACG)2 crosslinked bis-acridine complex' from the paper 'X-ray crystallographic study of DNA duplex cross-linking: simultaneous binding to two d(CGTACG)2 molecules by a bis(9-aminoacridine-4-carboxamide) derivative' by Nick Hopcroft, Anna Brogden, Mark Searcey and Christine Cardin, in the open access journal Nucleic Acids Research (OUP). The full reference is (2006) Nucleic Acids Res. 34: 6663-6672, doi 10.1093/nar/gkl930