ISBN: 978-83-60043-10-3 - eurobic9

L. Lista
Eurobic9, 2-6 September, 2008, Wrocław, Poland
P112. Heme-Protein Models: Toward Artificial Enzymes
Chemistry, University of Naples, via Cynthia, 80126, Naples, Italy
e-mail: lilista@unina.it
Metalloproteins are involved in fundamental biological processes and utilize a relatively small number of metal
based prosthetic groups to serve numerous chemical functions [1]. Heme-proteins represent a fascinating
example in this respect; a single prosthetic group, the heme, promotes a variety of functions such as dioxygen
transport and storage, electron transfer and catalysis of redox reactions [2]. In the last decades, numerous studies
have been devoted to the structure-activity relationships in hemoproteins: model compounds, able to reproduce
the structural and functional features of heme-proteins, represent a useful tools to elucidate the mechanism of
action of natural systems. A new class of heme-peptide conjugates have been developed in our laboratory [3],
with the aim of investigating the effects of peptide chain composition and folding in modulating the properties of
the metal ion inserted into the porphyrin ring. The main features are the covalent structure and a well defined
helical conformation of the peptide chains linked to the deuteroporphyrin ring [4]. Here, we present a
pentacoordinated metal ion porphyrin miniprotein, developed to allow the binding of exogenous ligands at the
sixth vacant position. This model is stable and water soluble and exhibits peroxidase activity. Structural and
functional data, compared to other model systems and natural peroxidases, will be presented.
References:
[1] a) S. J. Lippard, J.M. Berg, Principles of Bioinorganic Chemistry, University Science Books, Mill Valley,
CA, 1994; b) R. H: Holm, P. Kennepohl, E. I. Solomon, Chem. Rev. 1996, 96, 2239-2314.
[2] The Porphyrins, (Ed.: D. Dolphin), Academic Press, New York, 1979.
[3] A. Lombardi, F. Nastri, D. Marasco, O. Maglio, G. De Sanctis, F. Sinibaldi, R. Santucci, M. Coletta, V.
Pavone, Chem. Eur. J. 2003, 9, 5643-5654.
[4] A. Lombardi, F. Nastri, V. Pavone Chem. Rev. 2001, 101, 3165-3189.
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