Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding

Article English OPEN
Monari, S. ; Ranieri, A. ; Di Rocco, G. ; van der Zwan, G. ; Peressini, S. ; Tavagnacco, C. ; Millo, D. ; Borsari, M. (2009)

The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The much lower E°' value of the bis-histidinate conformer as compared to His-Met ligated species is largely determined by the enthalpic contribution induced by axial ligand substitution. The biphasic E°' versus T profile for the His-Met species is due to a difference in reduction entropy between the conformers at low and high temperatures. Enthalpy-entropy compensation phenomena for the reduction reaction at varying urea concentration for all the forms of the investigated cytochromes c were addressed and discussed. © 2009 Springer Science+Business Media B.V.
  • References (62)
    62 references, page 1 of 7

    1. Messerschmidt A, Huber R, Poulos T, Wieghardt K (eds) (2001) Handbook of metalloproteins. Wiley, Chichester, UK

    2. Scott RA, Mauk GA (eds) (1996) Cytochrome c: a multidisciplinary approach. University Science Books, Sausalito, CA

    3. Moore GR, Pettigrew GW (eds) (1990) Cytochromes c: evolutionary, structural, and physicochemical aspects. SpringerVerlag, Berlin

    4. Battistuzzi G, Borsari M, Sola M (2001) Eur J Inorg Chem 2989

    5. Bond AM (1994) Inorg Chim Acta 226:293

    6. Hill HAO, Hunt NI (1993) Methods Enzymol 227:501

    7. Armstrong FA (1990) Struct Bonding 72:137

    8. Armstrong FA, Hill HAO, Walton NJQ (1986) Rev Biophys 18:261

    9. Bryngelson JD, Onuchic JN, Socci ND, Wolynes PG (1995) Proteins 21:167

    10. Dobson CM, Sali A, Karplus M (1998) Angew Chem Int Ed 37:868

  • Metrics
    No metrics available
Share - Bookmark

  • Download from
    DSpace at VU via NARCIS (Article, 2009)
  • Cite this publication