Download MendeleyStructures of 1:1 and 2:1 complexes of BMVC and MYC promoter G-quadruplex reveal a mechanism of ligand conformation adjustment for G4-recognition.
Liu, W., Lin, C., Wu, G., Dai, J., Chang, T.C., Yang, D.(2019) Nucleic Acids Res 47: 11931-11942
- PubMed: 31740959
- DOI: https://doi.org/10.1093/nar/gkz1015
- Primary Citation of Related Structures:
6JJ0, 6O2L - PubMed Abstract:
BMVC is the first fluorescent probe designed to detect G-quadruplexes (G4s) in vivo. The MYC oncogene promoter forms a G4 (MycG4) which acts as a transcription silencer. Here, we report the high-affinity and specific binding of BMVC to MycG4 with unusual slow-exchange rates on the NMR timescale. We also show that BMVC represses MYC in cancer cells. We determined the solution structures of the 1:1 and 2:1 BMVC-MycG4 complexes. BMVC first binds the 5'-end of MycG4 to form a 1:1 complex with a well-defined structure. At higher ratio, BMVC also binds the 3'-end to form a second complex. In both complexes, the crescent-shaped BMVC recruits a flanking DNA residue to form a BMVC-base plane stacking over the external G-tetrad. Remarkably, BMVC adjusts its conformation to a contracted form to match the G-tetrad for an optimal stacking interaction. This is the first structural example showing the importance of ligand conformational adjustment in G4 recognition. BMVC binds the more accessible 5'-end with higher affinity, whereas sequence specificity is present at the weaker-binding 3'-site. Our structures provide insights into specific recognition of MycG4 by BMVC and useful information for design of G4-targeted anticancer drugs and fluorescent probes.
Organizational Affiliation:
Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, 575 W Stadium Ave, West Lafayette, IN 47907, USA.
