4) A major finding of this work is that domain 2 collapses but does not lose its structure (Results section). Earlier EM studies suggested it does lose its structure but modeling and FRET studies suggested otherwise. More discussion of this controversy is required. Importantly, the electron density of this key region should be shown in a figure to satisfy the reader that the structure has been maintained. (Figure 2E is not convincing enough. A stereo with side-chains focused on D2 only would be easier to evaluate). Some new detailed insights are discussed; namely, the remodeled helix-turn-helix motif and helix alpha3a. Can stereo figures of the electron density with side-chains displayed of these regions be shown?