Modulation of the Ligand-Field Anisotropy in a Series of Ferric Low-Spin Cytochrome c Mutants derived from Pseudomonas aeruginosa Cytochrome c-551 and Nitrosomonas europaea Cytochrome c-552: A Nuclear Magnetic Resonance and Electron Paramagnetic Resonance Study
| Autor: | K. Kristoffer Andersson, Kara L. Bren, Giorgio Zoppellaro, Ravinder Kaur, Espen Harbitz, Amy A. Ensign |
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| Rok vydání: | 2008 |
| Předmět: |
biology
Stereochemistry Cytochrome c Resonance General Chemistry Ligand (biochemistry) biology.organism_classification Biochemistry Catalysis law.invention chemistry.chemical_compound Colloid and Surface Chemistry Nuclear magnetic resonance chemistry Cytochrome C1 law Nitrosomonas europaea medicine biology.protein Ferric Electron paramagnetic resonance Heme medicine.drug |
| Zdroj: | Journal of the American Chemical Society. 130:15348-15360 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Cytochromes of the c type with histidine−methionine (His-Met) heme axial ligation play important roles in electron-transfer reactions and in enzymes. In this work, two series of cytochrome c mutants derived from Pseudomonas aeruginosa (Pa c-551) and from the ammonia-oxidizing bacterium Nitrosomonas europaea (Ne c-552) were engineered and overexpressed. In these proteins, point mutations were induced in a key residue (Asn64) near the Met axial ligand; these mutations have a considerable impact both on heme ligand-field strength and on the Met orientation and dynamics (fluxionality), as judged by low-temperature electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectra. Ne c-552 has a ferric low-spin (S = 1/2) EPR signal characterized by large g anisotropy with gmax resonance at 3.34; a similar large gmax value EPR signal is found in the mitochondrial complex III cytochrome c1. In Ne c-552, deletion of Asn64 (NeN64Δ) changes the heme ligand field from more axial to rhombic (small g ... |
| Databáze: | OpenAIRE |
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