Metalloproteins model system, metalloporphyrins

This leads us finally to a brief discussion of our recent work on metalloproteins, and their model systems, metalloporphyrins. Here, the basic longterm objectives are to obtain a better understanding of how CO and 02, and their isoelectronic counterparts the isocyanides (RNC) and nitrosoalkanes/nitrosoarenes (RNO), bind to Fe, as well as to probe the structure of cytochrome c, a small protein involved not only in electron-transfer, but in apoptosis, or programmed cell death (44). 

Abstract. We report the results of experimental and theoretical studies of 13C and 15N shifts in proteins and model systems, together with 57Fe shifts and Mossbauer quadrupole splittings (electric field gradients) in metalloporphyrins and metalloproteins. The ability to relate these spectroscopic observables to structure by using quantum chemical methods opens up new opportunities for predicting and refining protein structure. 

Metallopeptide models refer to systems that are mostly unstructured in solntion in the absence of metal ions. It is applicable to design of metal-binding sites whose conserved residues appear mostly in a single peptide that is often much shorter than the whole protein. Designing metalloproteins using only the peptide with the consensus sequence, often called a motif, represents the minimalist approach in its purest sense. These motifs typically contain His, Cys, or both residues. In addition, metalloporphyrin-containing peptides have also been made to mimic basic features in heme proteins. 

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