Identification of heme axial ligands of cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015

Yoshimura, Tetsuhiko; Suzuki, Shinnichiro; Nakahara, Akitsugu; Iwasaki, Hidekazu; Masuko, Masayuki; Matsubara, Takeo

doi:10.1016/0167-4838(85)90106-2

Cited by 42 publications

(37 citation statements)

References 41 publications

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“…While the assignment of the optical spectra of native cytochrome c to the heme ligands is possible due to the known X-ray structure, this is yet not the case for the multiple conformations induced by the variation of pH, temperature, ionic strength or denaturants. In the acid pH region (low ionic strength) the existence of high-spin state of cyt c or cytochrome c' was identified by several spectral methods [32][33][34] and is also confirmed by our EPR data (Fig. 2).…”

Section: Accepted Manuscript Discussionsupporting

confidence: 87%

Influence of NaCl and sorbitol on the stability of conformations of cytochrome c

Bágeľová

Fedunova

Gažová

et al. 2008

Biophysical Chemistry

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Influence of ionic (NaCl) and non-ionic (sorbitol) additives on structural transitions of cytochrome c was investigated by circular dichroism, optical and EPR spectroscopy. Transformations of cytochrome c, induced by the acidification of solution and temperature perturbation, were monitored in the heme pocket together with changes in the secondary structure. NaCl and sorbitol exhibited antagonistic effect on the acid-induced transition of the protein. Sorbitol enhanced the stability of native conformation while NaCl destabilized this state. The midpoints of acid-induced transitions in the axial coordination of heme as well as in the secondary structure occurred nearly at the same pH values. However, temperature-induced transitions in the unfolding of the secondary structure were almost coincidental with the cleavage of Met80-Fe bond only in the sorbitol solutions. In the salt solution the Met80-Fe bond was markedly more labile than the secondary structure.

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Section: Accepted Manuscript Discussionsupporting

confidence: 87%

Influence of NaCl and sorbitol on the stability of conformations of cytochrome c

Bágeľová

Fedunova

Gažová

et al. 2008

Biophysical Chemistry

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“…Also, the charge-transfer band at 643 nm increases in extinction but does not shift position. There is good evidence that the spectral changes in cytochrome c′ are due to the deprotonation of the histidine that is ligated to the heme iron and the resultant increase in the strength of Fe-histidine bond (Yoshimura et al, 1985). Therefore, for sGC, it is possible a Values for sGC were determined at 10 °C.…”

Section: Discussionmentioning

confidence: 99%

Spectral and Ligand-Binding Properties of an Unusual Hemoprotein, the Ferric Form of Soluble Guanylate Cyclase

et al. 1996

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The soluble form of guanylate cyclase (sGC) is a hemoprotein which serves as the only known receptor for the signaling agent nitric oxide (.NO). The enzyme is a heterodimer in which each subunit binds 1 equiv of 5-coordinate high-spin type b heme. .NO increases the Vmax of sGC up to 400-fold by binding to the heme to form a 5-coordinate ferrous nitrosyl complex. The electron paramagnetic resonance spectrum of the ferric form of the enzyme has been obtained. The spectrum displays rhombic symmetry and is indicative of a high-spin heme. Computer simulation of the EPR spectrum yields g values of 6.36, 5.16, and 2.0 with linewidths of 3.3, 4.1, and 3.3 mT, respectively. Using electronic absorption spectroscopy, it was observed that the ferric heme binds cyanide to form a 6-coordinate low-spin complex. The rate constants for association (k(on)) and dissociation (k(off)) of cyanide at 10 degrees C have been determined to be (7.8 +/- 0.3) x 10(-2) M(-1) s(- 1) and (7.2 +/- 0.2) x 10(-5) s(-1), respectively. Unlike the ferrous form of the enzyme, which has a low affinity for ligands that form 6-coordinate complexes due to an unusually fast off-rate, the ferric form of the enzyme appears to have a low affinity for ligands due to a slow on-rate. The ferric heme binds azide with a Kd of 26 +/- 4 mM to form a high-spin complex. The ferric form of the enzyme has a specific activity of approximately 57% that of the nonactivated ferrous form of the enzyme. However, in contrast to the mild activation of the ferrous enzyme by carbon monoxide, the ferric enzyme is not activated by cyanide. These results indicate that there may be a significant structural change in the protein upon the oxidation of the heme iron.

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“…A role in cyclic, photosynthetic electron transport has long been excluded [110]. It is also pertinent that cytochrome c' is found amongst the denitrifying bacteria [108,111], including Alcaligenes sp., which, as noted earlier~ also probably contains the copper-containing nitrous oxide reductase [99]. It will be of interest to learn if Pseudomonas perfectomarinus also contains cytochrome c'.…”

Section: Succinote -mentioning

confidence: 99%

Anaerobic respiration in the Rhodospirillaceae: characterisation of pathways and evaluation of roles in redox balancing during photosynthesis

Ferguson¹

1987

FEMS Microbiology Letters

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Identification of heme axial ligands of cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015

Cited by 42 publications

References 41 publications

Influence of NaCl and sorbitol on the stability of conformations of cytochrome c

Influence of NaCl and sorbitol on the stability of conformations of cytochrome c

Spectral and Ligand-Binding Properties of an Unusual Hemoprotein, the Ferric Form of Soluble Guanylate Cyclase

Anaerobic respiration in the Rhodospirillaceae: characterisation of pathways and evaluation of roles in redox balancing during photosynthesis

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