High-resolution crystal structure of cytochrome P450cam.

Structure and refinement of oxymyoglobin at 1·6 Å resolution

Information pertaining to the stereochemistry of metalloporphyrins and other tetrapyrroles continues to expand. The present article reviews important developments of this structural chemistry. Detailed updates on the relationship of the structure and physical properties of iron derivatives are given. Metalloporphyrins with unusually high or low oxidation states are reviewed. Surveys of recent work on π-cation radical complexes, bound O2 species, tetrapyrroles with N-substituents, the stereochemistry of ring-reduced tetrapyrroles and a variety of novel species are given. Newly developed data concerning experimental electron density studies are summarized. Detailed reviews of porphyrin-porphyrin (π-π) interactions in the solid state are given. A variety of important conformational aspects of metalloporphyrins and their consequent results on physical properties are presented. Finally, a number of isomorphous series and crystal packing effects in tetrapyrroles have been detailed.

Recent advances in the stereochemistry of metallotetrapyrroles

We have performed density functional theory (DFT) calculations of iron−porphyrin (FeP) and its complexes with O2, CO, NO, and imidazole (Im). Our fully optimized structures agree well with the available experimental data for synthetic heme models. Comparison with crystallographic data for proteins highlights interesting features of carbon monoxymyoglobin. The diatomic molecule induces a 0.3−0.4 A displacement of the Fe atom out of the porphyrin nitrogen (Np) plane and a doming of the overall porphyrin ring. The energy of the iron−diatomic bond increases in the order Fe−O2 (9 kcal/mol) < Fe−CO (26 kcal/mol) < Fe−NO (35 kcal/mol). The ground state of FeP(O2) is an open shell singlet. The bent Fe−O2 bond can be formally described as FeIII−O2-, and it is characterized by the anti-ferromagnetic coupling between one of the d electrons of Fe and one of the π* electrons of O2. FeP(CO) is a closed shell singlet, with a linear Fe−C−O bond. The complex with NO has a doublet ground state and a Fe−NO geometry intermed...

Equilibrium Geometries and Electronic Structure of Iron-Porphyrin Complexes: A Density Functional Study

Synthetic metal complexes can closely approach the properties of metal ions in proteins and yield useful information concerning biological structure and function.

https://science.sciencemag.org/content/sci/209/4453/223.full.pdf

Modeling coordination sites in metallobiomolecules

Structure of a dioxygen adduct of (1-methylimidazole)-meso-tetrakis(.alpha.,.alpha.,.alpha.,.alpha.,-o-pivalamidophenyl)porphinatoiron(II). An iron dioxygen model for the heme component of oxymyoglobin

A. Christopher Reed

Papers

Structure of a dioxygen adduct of (1-methylimidazole)-meso-tetrakis(.alpha.,.alpha.,.alpha.,.alpha.,-o-pivalamidophenyl)porphinatoiron(II). An iron dioxygen model for the heme component of oxymyoglobin