Theory 41/Nucleic Acid Biophysics
Hybridisation Is a Salt Ratio
The claim
Nucleic acid hybridisation rate is set by the ratio of salt concentration to duplex length rather than by salt alone, so long duplexes need more salt to reach the same rate.
01The mechanism
Electrostatic screening sets how easily strands approach; longer duplexes accumulate more charge and need more screening before the rate saturates.
02Predictions
- P1Rate should track the ratio.
- P2Salt alone should mispredict.
03Refutation
Rate tracking salt concentration would remove the length term.