Conclusion

1. The time constant of A, B and D helices are less than 4 ms.

2. Hydrophobic collapse occurs rapidly after the initiation of folding.

3. A, B and D helices undergo little exchange during folding, it means that helices ABD is likely the major region of the hydrophobic core.

4. The pulse labeling results show that following the formation of highly persisitent structure in A, B and D helix cluster in all molecules the next element which connects onto it and aquires persistent structure in the C helix. This makes many close contacts with the ABD cluster in the native molecular structure.

5. Trp108 and other aromatic residues from A, B and D helix cluster make contacts with C helix.

6. Fitted decay times and heterogeneity parameters suggest that individual structure elements fold in a local co-operative manner.