CFTR is a chain of 1480 beads. It's almost unimaginable that this protein machine consists of just a single chain, but it does. The beginning and end of the chain are indicated.
It helps that CFTR initially folds into 5 components. Then, it becomes a chain of 5 interconnected puzzle pieces (T1, N1, R, T2, N2, as shown in the drawing) that need to fit together. But even then, this process isn't achievable without assistance, and CFTR is just one of approximately 20,000 different proteins in our body that require folding.