Theory 42/Nucleic Acid Biophysics
Quadruplex Stability Is a Loop Ratio
The claim
G-quadruplex stability is set by the ratio of loop length to cation radius, so the same sequence folds differently with different ions.
01The mechanism
Cations stabilise the tetrad core by sitting between planes; loop length determines how much strain the backbone can relieve, and the two interact.
02Predictions
- P1Stability should track the ratio.
- P2Cation alone should mispredict.
03Refutation
Stability tracking cation would remove the loop term.