Proteins three finger structure

The ultimate goal of protein engineering is to design an amino acid sequence that will fold into a protein with a predetermined structure and function. Paradoxically, this goal may be easier to achieve than its inverse, the solution of the folding problem. It seems to be simpler to start with a three-dimensional structure and find one of the numerous amino acid sequences that will fold into that structure than to start from an amino acid sequence and predict its three-dimensional structure. We will illustrate this by the design of a stable zinc finger domain that does not require stabilization by zinc. 

Omichinski, J. G., Clore, G. M., Appella, E., Sakaguchi, K., and Gronenborn, A. M. (1990). High-resolution three-dimensional structure of a single zinc finger from a human enhancer binding protein in solution. Biochemistry 29, 9324-9334. 

Figure 5-37 Three-dimensional structure of a zinc finger. This is formed by the binding of Zn2+ to the following sequence in a protein ...

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