2cmm

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spinqualitylabelsall models 2cmm, resolution 1.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURAL ANALYSIS OF THE MYOGLOBIN RECONSTITUTED WITH IRON PORPHINE

Overview

Sperm whale apomyoglobin was complexed with iron porphine to examine the influence of completely removed heme side chains on the entire molecular structure. Paramagnetic NMR peak from the proximal histidine of the deoxy protein ensured formation of the iron-histidine bond. Porphine pyrrole-proton NMR signals of the cyanmet and deoxy derivatives are unusually sharp single lines manifesting rapid heme rotation about the iron-histidine bond. X-ray crystallographic structure of the cyanmet derivative, determined with a final R factor of 0.21 for 11,808 independent reflections ranging from 7 to 1.8 A, was resolved at 1.8 A resolution. The result confirmed 1:1 coupling between apomyoglobin and iron porphine. The cyano ligand adopts a bent configuration with an Fe-C-N angle of 127 degrees and a Fe-CN distance of 1.89 A. The overall globin structure and side chain conformations are remarkably similar to those of native myoglobin despite intensive disruption of the original heme-globin interactions. The native apoprotein structure unexpectedly conserved even after iron porphine insertion demonstrates that the complex polypeptide fold of holomyoglobin is more inherent in the amino acid sequence than is generally believed.

About this Structure

2CMM is a Single protein structure of sequence from Physeter catodon with and as ligands. Full crystallographic information is available from OCA.

Reference

Structural analysis of the myoglobin reconstituted with iron porphine., Neya S, Funasaki N, Sato T, Igarashi N, Tanaka N, J Biol Chem. 1993 Apr 25;268(12):8935-42. PMID:8473336

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