Heme proteins structure-function relationship

J. R. Kincaid, Resonance Raman Spectra of Heme Proteins and Model Compounds, in eds. K. M. Kadish, K. M. Smith and R. Guilard, The Porphyrin Handbook , Academic Press, New York, 2000, Vol. 7. An excellent review that summarizes and clearly illustrates the power of RR spectroscopy in probing structure-function relationships for a wide variety of heme proteins. 

The study of model compounds or simply, models of heme proteins is very helpful in elucidating structure-function relationships. Models are compounds with low molecular weight that imitate struetural, spectroscopic, or functional details of the original enzymes. The latter are macromolecules and hence more difficult to study. Synthetic models for states 7-5 must be thiolate-ligated. Such models have been prepared and extensively characterized. The models from several laboratories have recently been reviewed [22]. A model system having a ferric-peroxide composition, as is present in 6, has also been described [40]. Relevant models are listed in the tables (see Sects. 3.1 and 4.1.1). Model chemistry has been extremely important in characterizing these intermediates. 

Probing the Structure-Function Relationship OF Heme Proteins Using Multifrequency... 

While these complex model heme proteins have a large potential for functionalization, an interesting approach that is very different has been taken by other workers in that the heme itself functions as the template in the formation of folded peptides. In these models peptide-peptide interactions are minimized and the driving force for folding appears to be the interactions between porphyrin and the hydrophobic faces of the amphiphiUc peptides. The amino acid sequences are too small to permit peptide-peptide contacts as they are separated by the tetrapyrrole residue. These peptide heme conjugates show well-re-solved NMR spectra and thus well-defined folds and the relationship between structure and function can probably be determined in great detail when functions have been demonstrated [22,23,77]. They are therefore important model systems that complement the more complex proteins described above. 

Myoglobin in many respects is the prototypical example of the larger family of heme containing proteins and enzymes that vary in function from the relatively simple process of reversible binding of an electron to the activation of dioxygen for substrate hydroxylation. The relationship between members of this family of proteins is not based simply on structural similarities but on similarities in chemical reactivity as well. As the structure of myoglobin is relatively simple compared to other heme proteins and as it was the first for which the three-dimensional... 

Stefano Bettati received his MS degree from the University of Parma in 1992, defending a thesis on The allosteric regulation of the enzyme tryptophan synthase, and his Ph.D. degree in 1998 from the University of Modena, by working on hemoglobin. He was a postdoctoral fellow at the laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA, from 1999 to 2000. At present he is a full professor at Applied Physics, Faculty of Medicine, University of Parma, Italy. His current research interests are mainly in structure, function, and dynamics relationships of PLP-dependent enzymes, heme proteins, and green fluorescent proteins. 

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