Utilization of Nitric Oxide as a Paramagnetic Probe of the Molecular Oxygen Binding Site of Metalloenzymes

Nitric oxide (NO) is a physiologically relevant activator of the hemoprotein soluble guanylate cyclase (sGC). In the presence of NO, sGC is activated several hundredfold above the basal level by a mechanism that remains to be elucidated. The heme ligand n-butyl isocyanide (BIC) was used to probe the mechanism of NO activation of sGC. Electronic absorption spectroscopy was used to show that BIC binds to the sGC heme, forming a 6-coordinate complex with an absorbance maximum at 429 nm. BIC activates sGC 2-5-fold, and synergizes with the allosteric activator YC-1, to activate the enzyme 15-25-fold. YC-1 activates the sGC-BIC complex, and leads to an increase in both the Vmax and Km. BIC was also used to probe the mechanism of NO activation. The activity of the sGC-BIC complex increases 15-fold in the presence of NO, without displacing BIC at the heme, which is consistent with previous reports that proposed the involvement of a non-heme NO binding site in the activation process.

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Catalytic reduction of nitric oxide and molecular oxygen by carbon monoxide in the presence of a platinum(0)diphosphine complex in solution at ambient conditions

Inorganica Chimica Acta ◽

10.1016/s0020-1693(00)94956-9 ◽

1978 ◽

Vol 31 ◽

pp. L443-L444 ◽

Cited By ~ 16

Author(s):

Chong-Shik Chin ◽

Michael S. Sennett ◽

Patrick J. Wier ◽

L. Vaska

Keyword(s):

Nitric Oxide ◽

Carbon Monoxide ◽

Molecular Oxygen ◽

Catalytic Reduction ◽

Ambient Conditions

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Oxygen binding isotope effects of triazole-based HIV-1 reverse transcriptase inhibitors indicate the actual binding site

Archives of Biochemistry and Biophysics ◽

10.1016/j.abb.2017.10.017 ◽

2017 ◽

Vol 635 ◽

pp. 87-95

Author(s):

Agnieszka Krzemińska ◽

Tomasz Frączek ◽

P. Paneth

Keyword(s):

Reverse Transcriptase ◽

Binding Site ◽

Isotope Effects ◽

Oxygen Binding ◽

Reverse Transcriptase Inhibitors ◽

Hiv 1

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Utilization of Nitric Oxide as a Paramagnetic Probe of the Molecular Oxygen Binding Site of Metalloenzymes

Studies of the oxygen binding site of cytochrome P-450. Nitric oxide as a spin-label probe.

The cytochrome c oxidase-azide-nitric oxide complex as a model for the oxygen-binding site

The pteridine binding site of brain nitric oxide synthase. Tetrahydrobiopterin binding kinetics, specificity, and allosteric interaction with the substrate domain.

Probing the oxygen binding site of cytochrome c oxidase by cyanide.

Effective Photodissociation Cross Sections for Molecular Oxygen and Nitric Oxide in the Schumann-Runge Bands

Structure of Dioclea virgata lectin: Relations between carbohydrate binding site and nitric oxide production

A computational investigation of the reactions of tyrosyl, tryptophanyl, and cysteinyl radicals with nitric oxide and molecular oxygen

Butyl Isocyanide as a Probe of the Activation Mechanism of Soluble Guanylate Cyclase

Catalytic reduction of nitric oxide and molecular oxygen by carbon monoxide in the presence of a platinum(0)diphosphine complex in solution at ambient conditions

Oxygen binding isotope effects of triazole-based HIV-1 reverse transcriptase inhibitors indicate the actual binding site

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