Involvement of the hydrophobic patch of azurin in the electron‐transfer reactions with cytochrome c551 and nitrite reductase

1990/11/01 by Mart van de KAMP, Mart van de Kamp, Maria Chiara SILVESTRINI +9 · 12 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Energy · #Azurin #Biochemistry #Chemistry #Cytochrome #Electron transfer #Electron transport chain #Enzyme #Inorganic chemistry #Metalloenzymes and iron-sulfur proteins #Nitrite #Nitrite reductase #Organic chemistry #Photochemistry #Photosynthetic Processes and Mechanisms #Porphyrin Metabolism and Disorders #Redox #Stereochemistry

paper · pdf · doi:10.1111/j.1432-1033.1990.tb19434.x

openalex publication_date 1990/11/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/27

Abstract

The electron-transfer reactions of site-specific mutants of the blue copper protein azurin from Pseudomonas aeruginosa with its presumed physiological redox partners cytochrome c551 and nitrite reductase were investigated by temperature-jump and stopped-flow experiments. In the hydrophobic patch of azurin Met44 was replaced by Lys, and in the His35 patch His35 was replaced by Phe, Leu and Gln. Both patches were previously thought to be involved in electron transfer. 1H-NMR spectroscopy revealed only minor changes in the three-dimensional structure of the mutants compared to wild-type azurin. Observed changes in midpoint potentials could be attributed to electrostatic effects. The slow relaxation phase observed in temperature-jump experiments carried out on equilibrium mixtures of wild-type azurin and cytochrome c551 was definitively shown to be due to a conformational relaxation involving His35. Analysis of the kinetic data demonstrated the involvement of the hydrophobic but not the His35 patch of azurin in the electron transfer reactions with both cytochrome c551 and nitrite reductase.

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• Global Sequence Analysis and Expression of Azurin Gene in Different Clinical Specimens of Burn Patients with Pseudomonas aeruginosa Infection. [europepmc]
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• A cytochrome c 551 mediates the cyclic electron transport chain of the anoxygenic phototrophic bacterium Roseiflexus castenholzii. [europepmc]
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• Transient Absorption Spectroscopy of Blue Copper Sites in Divergent Protein Folds: Azurin Versus Multicopper Oxidase. [europepmc]

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