Attached is an image showing different crystal structures of the same protein in diffrent states (mutant vs substrate bound vs unliganded)  and highlighted are little changes in secondary structure. I was wondering how real such small changes are and if they are real could they be enough to perturb the energy potential of the protein significantly. 

I apologize if this is a naive question as this is clearly not my area of expertise.

Thanks for your input 

Mahesh