Theory 40/Protein Folding
Chaperones Need a Rate Gap
The claim
Whether a protein requires chaperones is set by the ratio of its folding rate to translation rate, so a slow-folding domain on a fast ribosome needs help.
01The mechanism
Folding begins while the chain is still emerging; if folding is slower than synthesis, exposed segments accumulate and aggregate unless chaperones bind them.
02Predictions
- P1Requirement should track the rate ratio.
- P2Domain size alone should mispredict.
03Refutation
Requirement tracking size would remove the rate term.