First Tandem Repeat of a Potassium Channel KCNN4 Minisatellite Folds into a V-Loop G-Quadruplex Structure.
Vianney, Y.M., Weisz, K.(2021) Biochemistry 60: 1337-1346
- PubMed: 33844501
- DOI: https://doi.org/10.1021/acs.biochem.1c00043
- Primary Citation of Related Structures:
7ATZ - PubMed Abstract:
The KCNN4 gene encoding a potassium channel protein whose expression has been correlated with tumor progression was found to comprise a guanine-rich minisatellite region with the ability to form a putative G-quadruplex (G4). Given the suggested regulatory role of G4s in gene expression, G-quadruplex formation for the polymorphic first repeat of the minisatellite was studied by nuclear magnetic resonance spectroscopy. A stable G-quadruplex of a truncated mutant sequence was shown to represent one of several coexisting species of the wild-type sequence. The high-resolution structure features a noncanonical G4 with a broken G-column and a V-shaped loop. The presence of a 3'-flanking thymidine interacting with the lateral loop preceding the V loop seems to be critical for the formation of this G4 topology. On the contrary, an additional 5'-flanking residue disfavored but still allowed folding into the V-loop structure. The latter may therefore serve as a putative therapeutic target in strategies for G4-based modulation of KCNN4 expression.
Organizational Affiliation:
Institute of Biochemistry, Universität Greifswald, Felix-Hausdorff-Strasse 4, D-17487 Greifswald, Germany.