Summary information and primary citation

PDB-id
1l1v; SNAP-derived features in text and JSON formats; DNAproDB
Class
DNA-antibiotic
Method
NMR
Summary
Unusual actd-dna_ta complex structure
Reference
Chou SH, Chin KH, Chen FM (2002): "Looped Out and Perpendicular: Deformation of Watson-Crick Base Pair Associated with Actinomycin D Binding." Proc.Natl.Acad.Sci.USA, 99, 6625. doi: 10.1073/PNAS.102580399.
Abstract
Many anticancer drugs interact directly with DNA to exert their biological functions. To date, all noncovalent, intercalating drugs interact with DNA exclusively by inserting their chromophores into base steps to form elongated and unwound duplex structures without disrupting the flanking base pairs. By using actinomycin D (ActD)-5'-GXC/CYG-5' complexes as examples, we have found a rather unusual interaction mode for the intercalated drug; the central Watson-Crick X/Y base pairs are looped out and displaced by the ActD chromophore. The looped-out bases are not disordered but interact perpendicularly with the base/chromophore and form specific H bonds with DNA. Such a complex structure provides intriguing insights into how ligand interacts with DNA and enlarges the repertoires for sequence-specific DNA recognition.

Cartoon-block schematics in six views (download the tarball)

PyMOL session file Download PDB file View in 3Dmol.js