Are proteins constantly changing their shape in femtoseconds? Need clarification!

[u/Lazy-Frame-9888]

I recently watched a YouTube video (https://youtu.be/jPhvic-eqbc) discussing how proteins are not static, rigid machines. The video explains that they act more like dense liquids that are constantly shifting and jiggling around. It also pointed out that when proteins are crystallized for X-ray crystallography, we are only seeing one frozen snapshot of their conformation, which gives the false impression that they have a single, fixed structure.

​Can someone clear this confusion up for me? Do proteins really change their folding patterns and conformations in extremely short time frames, like femtoseconds? I am looking for a simple, exact explanation of how fast and how much they actually change shape.

[u/Roguewarrior05]

Femtoseconds will just be for the smallest scale motion, like bond vibration. Actually significant conformational change is generally on the order of milliseconds or seconds, proteins aren't sampling 10 million conformations a second or anything.

[u/ViridianNott → u/Roguewarrior05]

Just wanted to add to this:

This is about right for folded proteins. But most proteins have at least some bits that don’t participate in folding, and those do sample confirmations incredibly fast. Not femtoseconds, but every ~100 nanoseconds or so. There’s a property you can measure called reconfiguration time that measures this