Abstract
The Mossbauer effect associated with 129I, 125Te, and 57Fe has been applied to investigate structural properties of the axial ligands in ferric-high spin hematoheme-I, hematoheme-Te, and hematoheme-histidine-iodide. The magnitude and sign of the 129I quadrupole coupling constant (e2qQ) and the isomer shift, as deduced from the Mossbauer effect spectra, are consistent with an axial, s-p hybridized bond of overwhelming σ-character. Identical coupling constant (e2qQ(127I) = -1826 ± 3 MHz) were measured for both heme-I and hematoheme-histidine-iodide. Implications of this result to the nature of ferric-high spin heme-histidine complexing are discussed. A stable heme 125Te species formed in the electron-capture decay of heme-125I is observed, and structural properties of this singly bonded telluride ligand are discussed.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- KOENIG D. F. THE STRUCTURE OF ALPHA-CHLOROHEMIN. Acta Crystallogr. 1965 Apr 10;18:663–673. doi: 10.1107/s0365110x65001536. [DOI] [PubMed] [Google Scholar]
- Moss T. H., Bearden A. J., Caughey W. S. Mössbauer studies of bonding in iron porphyrin-ligand systems. J Chem Phys. 1969 Sep 15;51(6):2624–2631. doi: 10.1063/1.1672387. [DOI] [PubMed] [Google Scholar]
- Scholes C. P. Hyperfine structure from the four pyrrole nitrogens of heme. Proc Natl Acad Sci U S A. 1969 Feb;62(2):428–431. doi: 10.1073/pnas.62.2.428. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Warme P. K., Hager L. P. Heme sulfuric anhydrides. I. Synthesis and reactions of mesoheme sulfuric anhydride. Biochemistry. 1970 Mar 31;9(7):1599–1605. doi: 10.1021/bi00809a019. [DOI] [PubMed] [Google Scholar]