Jason M. Shearer, PhD , University of Nevada (Reno)
Thus we turned our attentions to the creation of synthetic myoglobins. This has practical applications in the preparation of synthetic blood, and may also give insight into the limitations of the creation of synthetic pPNA oxidation synzymes. Two pPNA segments were prepared. One had Fe-protopophyrin-IX covalently bound to an N-terminal lysine residue, while the other had a histidine residue to bind the Fe-center. A smaller PNA segment was utilized than before (the Dickerson dodecomer sequence was not used) that provided excellent stability through PNA base pairing and easier synthesis/purification. We placed a tryptophan residue to provide hydrogen-bonding to O2 in the peptide sequence in such a manner that it would a) provide stability to the bound O2, b) not coordinate to the Fe-center and c) disrupt the binding of other ligands. It was found that we could reversibly bind O2 in water as a function of O2 pressure and disfavor N3– and NO binding. CO binding was found to not be disrupted. We are currently writing this up for rapid communication in early 2012.