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

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.

[1]  Walter J. Murphy,et al.  ADVANCES IN CHEMISTRY SERIES: Numbers 15 and 17 Demonstrate Rapidly Crowing Interest in Documentation; International Conference To Be Held in 1958 , 1956 .

[2]  Michael L. Quillin,et al.  Structural and functional effects of apolar mutations of the distal valine in myoglobin. , 1995, Journal of molecular biology.

[3]  M. Kataoka,et al.  Role of heme axial ligands in the conformational stability of the native and molten globule states of horse cytochrome c. , 1996, Journal of molecular biology.

[4]  A. Wada,et al.  ‘Molten‐globule state’: a compact form of globular proteins with mobile side‐chains , 1983, FEBS letters.

[5]  G. Brayer,et al.  High-resolution three-dimensional structure of horse heart cytochrome c. , 1990, Journal of molecular biology.

[6]  S. Kidokoro,et al.  Thermodynamic characterization of cytochrome c at low pH. Observation of the molten globule state and of the cold denaturation process. , 1992, Journal of molecular biology.

[7]  M. Antalík,et al.  Conformational Transitions of Ferricytochrome c in Strong Inorganic Acids , 2006 .

[8]  E. Sedlák.  Characterization of the polyanion-induced molten globule-like state of cytochrome c. , 2007, Biopolymers.

[9]  V. Bychkova,et al.  Solvent dependence of dimensions of unfolded protein chains. , 1991, International journal of biological macromolecules.

[10]  H. Gray,et al.  Protein Folding Triggered by Electron Transfer , 1996, Science.

[11]  S. N. Timasheff,et al.  Control of protein stability and reactions by weakly interacting cosolvents: the simplicity of the complicated. , 1998, Advances in protein chemistry.

[12]  Y. Tan,et al.  Comparison of the conformational stability of the molten globule and native states of horse cytochrome c. Effects of acetylation, heat, urea and guanidine-hydrochloride. , 1994, Journal of molecular biology.

[13]  Harry B. Gray,et al.  Structurally engineered cytochromes with novel ligand-binding sites: oxy and carbon monoxy derivatives of semisynthetic horse heart Ala80 cytochrome c , 1993 .

[14]  D. Allen,et al.  Osmolyte-induced changes in protein conformational equilibria. , 2000, Biopolymers.

[15]  E. Shechter,et al.  Conformation of ferricytochrome c. IV. Relationship between optical absorption and protein conformation. , 1967, Biopolymers.

[16]  E. Margoliash,et al.  Appendix—Spectrum of horse-heart cytochrome c , 1959 .

[17]  M. Masuko,et al.  Identification of heme axial ligands of cytochrome c' from Alcaligenes sp. N.C.I.B. 11015. , 1985, Biochimica et biophysica acta.

[18]  S. Yadav,et al.  Conformational and thermodynamic characterization of the molten globule state occurring during unfolding of cytochromes-c by weak salt denaturants. , 2003, Biochemistry.

[19]  J. Winkler.  Cytochrome c folding dynamics. , 2004, Current opinion in chemical biology.

[20]  Y H Chen,et al.  Determination of the secondary structures of proteins by circular dichroism and optical rotatory dispersion. , 1972, Biochemistry.

[21]  J. Peisach,et al.  Low—Spin Compounds of Heme Proteins , 1971 .

[22]  M. Kataoka,et al.  Molten globule of cytochrome c studied by small angle X-ray scattering. , 1993, Journal of molecular biology.

[23]  G. Pielak,et al.  A native tertiary interaction stabilizes the A state of cytochrome c. , 1995, Biochemistry.

[24]  Y. Goto,et al.  Role of electrostatic repulsion in the acidic molten globule of cytochrome c. , 1991, Journal of molecular biology.

[25]  C. Sanders,et al.  Coordination structure of the ferric heme iron in engineered distal histidine myoglobin mutants. , 1992, The Journal of biological chemistry.

[26]  I. Nishii,et al.  Acid-induced unfolding and refolding transitions of cytochrome c: a three-state mechanism in H2O and D2O. , 1993, Biochemistry.

[27]  G. Palmer.  The electron paramagnetic resonance of metalloproteins. , 1985, Biochemical Society transactions.

[28]  B. R. Sreenathan,et al.  The insensitivity of the 695 nm band of horse heart ferricytochrome c to protein conformation. , 1971, Biochemical and biophysical research communications.

[29]  A. Fink,et al.  Mechanism of acid-induced folding of proteins. , 1990, Biochemistry.

[30]  A. Fontana,et al.  Partly folded states of members of the lysozyme/lactalbumin superfamily: A comparative study by circular dichroism spectroscopy and limited proteolysis , 2002, Protein science : a publication of the Protein Society.

[31]  S. Kidokoro,et al.  Direct observation of the enthalpy change accompanying the native to molten-globule transition of cytochrome c by using isothermal acid-titration calorimetry. , 2005, Biophysical chemistry.

[32]  A. Desideri,et al.  Formation of a molten-globule-like state of cytochrome c induced by high concentrations of glycerol. , 1999, Biochimie.

[33]  K. Gekko,et al.  Polyol-induced molten globule of cytochrome c: an evidence for stabilization by hydrophobic interaction. , 1999, Biochimica et biophysica acta.

[34]  Sugar-induced molten-globule model. , 1998, Biochemistry.

[35]  Y H Chen,et al.  Determination of the helix and beta form of proteins in aqueous solution by circular dichroism. , 1974, Biochemistry.

[36]  A. Fink,et al.  Acid-induced folding of proteins. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[37]  H. Fukada,et al.  Salt-induced formation of the molten globule state of cytochrome c studied by isothermal titration calorimetry. , 1994, Proceedings of the National Academy of Sciences of the United States of America.