Actually (and I'm sure N will correct me if I'm in error), the shape is often what counts in terms of activity at least for proteins.
Absolutely! I've pointed this out to Southack a number of times. For instance, in #606 "One very obvious way in [computer programming] isn't analogous is the secondary, 3^0, or 4^0 structures of DNA and the function inherent in those structures. This function is context dependent. For instance, if you drop a protein or DNA in an acid or a base, its function changes because of conformational changes, even though the sequence is still the same. Likewise, some proteins are dependent on the presence of certain heavy metal ions which induce the proper conformational structure.