Several studies have shown that anions induce collapse of acid-denatured cytochrome c into the compact A state having the properties of the molten globule and that the anion charge is the main determinant for the A state stabilization. The results here reported show that the anion size plays a role in determining the overall structure of the A state. In particular, small anions induce formation of an A state in which the native Met80-Fe(III) axial bond is recovered and the nativelike redox properties restored. On the other hand, the A state stabilized by large anions shows a hisfidine (His26 or His33) as the sixth ligand of the heme-iron, a very weak interaction between Trp59 and the heme propionate, and lacks nativelike redox properties. The two anion-stabilized states show similar stability, indicating that (i) the hydrophobic core (which is equally stabilized by all the anions investigated, independently of their size) is the region that mainly contributes to the macromolecule stabilization, and (ii) the flexible loops are responsible for the spectroscopic (and, thus, structural) and redox differences observed.

Santucci, R., Bongiovanni, C., Mei, G., Ferri, T., Polizio, F., Desideri, A. (2000). Anion size modulates the structure of the a state of cytochrome c. BIOCHEMISTRY, 39(41), 12632-12638 [10.1021/bi000516v].

Anion size modulates the structure of the a state of cytochrome c

SANTUCCI, ROBERTO;MEI, GIAMPIERO;POLIZIO, FRANCESCA;DESIDERI, ALESSANDRO
2000-01-01

Abstract

Several studies have shown that anions induce collapse of acid-denatured cytochrome c into the compact A state having the properties of the molten globule and that the anion charge is the main determinant for the A state stabilization. The results here reported show that the anion size plays a role in determining the overall structure of the A state. In particular, small anions induce formation of an A state in which the native Met80-Fe(III) axial bond is recovered and the nativelike redox properties restored. On the other hand, the A state stabilized by large anions shows a hisfidine (His26 or His33) as the sixth ligand of the heme-iron, a very weak interaction between Trp59 and the heme propionate, and lacks nativelike redox properties. The two anion-stabilized states show similar stability, indicating that (i) the hydrophobic core (which is equally stabilized by all the anions investigated, independently of their size) is the region that mainly contributes to the macromolecule stabilization, and (ii) the flexible loops are responsible for the spectroscopic (and, thus, structural) and redox differences observed.
2000
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/10 - BIOCHIMICA
English
Con Impact Factor ISI
anion; cytochrome c; article; circular dichroism; enzyme analysis; enzyme denaturation; enzyme stability; enzyme structure; molecular size; oxidation reduction state; priority journal; structure analysis; Animal; Anions; Circular Dichroism; Cytochrome c; Electrochemistry; Electron Spin Resonance Spectroscopy; Horses; Hydrogen-Ion Concentration; Models, Chemical; Oxidation-Reduction; Perchloric Acid; Protein Denaturation; Protein Folding; Salts; Sodium Chloride; Sodium Compounds; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Structure-Activity Relationship; Temperature; Thermodynamics; Titrimetry
Santucci, R., Bongiovanni, C., Mei, G., Ferri, T., Polizio, F., Desideri, A. (2000). Anion size modulates the structure of the a state of cytochrome c. BIOCHEMISTRY, 39(41), 12632-12638 [10.1021/bi000516v].
Santucci, R; Bongiovanni, C; Mei, G; Ferri, T; Polizio, F; Desideri, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/49988
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