Question

How long will it take the polypeptide backbone of a 6-residue chain to sample all possible confirmations? a 12-residue chain?

Answer 1

It will take the polypeptide backbone of a 6-residue chain to sample all possible confirmations ~ 6 ms (= 6*10^-3 s)

It will take the polypeptide backbone of a 12-residue chain to sample all possible confirmations ~ 12 ms

Explanation: In literature, it is reported that for 100-residue proteins, 3*10⁷ distinct topomers are found and it diffusively samples one topomer every ~ 3 ns (= 3*10^-9 s). Hence, a 100-residue protein can find its native topomer by random sampling in ~ 3*10⁷*3*10^-9 s ~ 10²*10^-3 s = 100 ms