1pyz
From Proteopedia
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CRYSTALLOGRAPHIC STRUCTURE OF MIMOCHROME IV
Overview
Protein design provides an attractive approach to test the essential, features required for folding and function. Previously, we described the, design and structural characterization in solution of mimochromes, a, series of miniaturized metalloproteins, patterned after the F-helix of the, hemoglobin beta-chain. Mimochromes consist of two medium-sized helical, peptides, covalently linked to the deuteroporphyrin. CD and NMR, characterization of the prototype, mimochrome I, revealed that the overall, structure conforms well to the design. However, formation of Delta and, Lambda diastereomers was observed. To overcome the problem of diastereomer, formation, we re-designed mimochrome I, by engineering intramolecular, interchain interactions. The resulting model was mimochrome IV: the, solution structural characterization showed the presence of the Lambda, isomer as a unique form. To examine the extent to which the stereochemical, stability and uniqueness of mimochrome IV was retained in the solid state, the crystal structure of Co(III)-mimochrome IV was solved by X-ray, diffraction, and compared to the solution structure of the same, derivative. Co(III)-mimochrome IV structures, both in solution and in the, solid state, are characterized by the following common features: a bis-His, axial coordination, a Lambda configuration around the metal ion, and a, predominant helical conformation of the peptide chains. However, in the, crystal structure, intrachain Glu1-Arg9 ion pairs are preferred over the, designed, and experimentally found in solution, interchain interactions., This ion pairing switch may be related to strong packing interactions.
About this Structure
1PYZ is a Protein complex structure of sequences from [1] with CL, ACE, NH2 and DEU as ligands. Full crystallographic information is available from OCA.
Reference
Miniaturized heme proteins: crystal structure of Co(III)-mimochrome IV., Di Costanzo L, Geremia S, Randaccio L, Nastri F, Maglio O, Lombardi A, Pavone V, J Biol Inorg Chem. 2004 Dec;9(8):1017-27. Epub 2004 Nov 13. PMID:15551102
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