Download MendeleyHigh resolution crystal structure of a KRAS promoter G-quadruplex reveals a dimer with extensive poly-A pi-stacking interactions for small-molecule recognition.
Ou, A., Schmidberger, J.W., Wilson, K.A., Evans, C.W., Hargreaves, J.A., Grigg, M., O'Mara, M.L., Iyer, K.S., Bond, C.S., Smith, N.M.(2020) Nucleic Acids Res 48: 5766-5776
- PubMed: 32313953
- DOI: https://doi.org/10.1093/nar/gkaa262
- Primary Citation of Related Structures:
6N65, 6WCK - PubMed Abstract:
Aberrant KRAS signaling is a driver of many cancers and yet remains an elusive target for drug therapy. The nuclease hypersensitive element of the KRAS promoter has been reported to form secondary DNA structures called G-quadruplexes (G4s) which may play important roles in regulating KRAS expression, and has spurred interest in structural elucidation studies of the KRAS G-quadruplexes. Here, we report the first high-resolution crystal structure (1.6 Å) of a KRAS G-quadruplex as a 5'-head-to-head dimer with extensive poly-A π-stacking interactions observed across the dimer. Molecular dynamics simulations confirmed that the poly-A π-stacking interactions are also maintained in the G4 monomers. Docking and molecular dynamics simulations with two G4 ligands that display high stabilization of the KRAS G4 indicated the poly-A loop was a binding site for these ligands in addition to the 5'-G-tetrad. Given sequence and structural variability in the loop regions provide the opportunity for small-molecule targeting of specific G4s, we envisage this high-resolution crystal structure for the KRAS G-quadruplex will aid in the rational design of ligands to selectively target KRAS.
Organizational Affiliation:
School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia.
