Zn(II) is ubiquitous is metalloproteins serving in both structural and catalytic roles. The Gibney group is utlizing the ferredoxin maquettes, sixteen amino acid peptides originally designed to bind [4Fe-4S] clusters, to design structural and catalytic Zn(II) peptides. We have evaluated the absolute affinities of the peptides for [4Fe-4S], Zn(II), Co(II) and Fe(II) sites to define the thermodynamics relevant to structural metal sites. In collaboration with Prof. Tierney (University of New Mexico), we are exploring the use of nonnatural amino acids such as penicillamine and homocysteine to generate asymmetric coordination environments similar to those observed for natural Zn(II) enzymes.