1vl3
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(New page: 200px<br /><applet load="1vl3" size="450" color="white" frame="true" align="right" spinBox="true" caption="1vl3" /> '''DESIGN OF NEW MIMOCHROMES WITH UNIQUE TOPOLO...)
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Revision as of 20:36, 24 November 2007
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DESIGN OF NEW MIMOCHROMES WITH UNIQUE TOPOLOGY
Overview
Peptide-based metalloprotein models represent useful systems to help, understand how metalloproteins can support different functions, by the use, of similar metal ion cofactors. In order to shed light on the role of the, protein matrix in modulating the heme properties, we developed new models:, mimochromes. They are pseudo-C(2) symmetric systems, composed of two, helical peptides covalently linked to the deuteroporphyrin. The use of, C(2) symmetry is particularly advantageous, because it simplifies the, design, synthesis and characterization. However, it leaves the problem of, possible diastereomeric forms. In the cobalt complex of the first, derivative, mimochrome I, Lambda and Delta isomers were indeed, experimentally observed. All the insights derived from the, Co(III)-mimochrome I structure were used to obtain a re-designed molecule, mimochrome IV. The spectroscopic characterization of the iron and cobalt, derivatives suggested the presence of the Lambda isomer as unique species., The NMR solution structure of the diamagnetic Co(III)-mimochrome IV, confirmed the ability of the molecule to adopt a unique topology, and, revealed the peptide chains to be in helical conformation, as designed., The insertion of intramolecular, inter-chain interactions was successful, in favoring the formation of one of the two possible diastereomers. The, stereochemically stable structure of mimochrome IV provides an attractive, model for modulating the redox potential of the heme, by simple changing, the peptide chain composition around the heme.
About this Structure
1VL3 is a Protein complex structure of sequences from [1] with DEU as ligand. This structure superseeds the now removed PDB entry 1L1B. Full crystallographic information is available from OCA.
Reference
Design of a new mimochrome with unique topology., Lombardi A, Nastri F, Marasco D, Maglio O, De Sanctis G, Sinibaldi F, Santucci R, Coletta M, Pavone V, Chemistry. 2003 Nov 21;9(22):5643-54. PMID:14639648
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