Abstract
The equilibrium and kinetic folding/unfolding of apomyoglobin (ApoMb) were studied at pH 6.2, 11 °C by recording tryptophan fluorescence. The equilibrium unfolding of ApoMb in the presence of urea was shown to involve accumulation of an intermediate state, which had a higher fluorescence intensity as compared with the native and unfolded states. The folding proceeded through two kinetic phases, a rapid transition from the unfolded to the intermediate state and a slow transition from the intermediate to the native state. The accumulation of the kinetic intermediate state was observed in a wide range of urea concentrations. The intermediate was detected even in the region corresponding to the unfolding limb of the chevron plot. Urea concentration dependence was obtained for the observed folding/unfolding rate. The shape of the dependence was compared with that of two-state proteins characterized by a direct transition from the unfolded to the native state.
Similar content being viewed by others
REFERENCES
Cavagnero S., Dyson H.J., Wright P.E. 1999. Effect of H helix destabilizing mutations on the kinetic and equilibrium folding of apomyoglobin. J. Mol. Biol. 285, 269–282.
Laurents D.V., Corrales S., Elias-Arnanz M., Sevilla P., Rico M., Padmanabhan S. 2000. Folding kinetics of phage 434 Cro protein. Biochemistry. 39, 13963–13973.
Tang K.S., Guralnick B.J., Wang W.K., Fersht A.R., Itzhaki L.S. 1999. Stability and folding of the tumour suppressor protein p16. J. Mol. Biol. 285, 1869–1886.
Parker M.J., Dempsey C.E, Lorch M., Clarke A.R. 1997. Acquisition of native beta-strand topology during the rapid collapse phase of protein folding. Biochemistry. 36, 13396–13405.
Burns L.L., Dalessio P.M., Ropson I.J. 1998. Folding mechanism of three structurally similar beta-sheet proteins. Proteins. 33, 107–118.
Schreiber G., Fersht A.R. 1993. The refolding of cis-and trans-peptidylprolyl isomers of barstar. Biochemistry. 32, 11195–11203.
Munoz V., Lopez E.M., Jager M., Serrano L. 1994. Kinetic characterization of the chemotactic protein from Escherichia coli, CheY. Kinetic analysis of the inverse hydrophobic effect. Biochemistry. 33, 5858–5866.
Parker M.J., Marqusee S. 1999. The cooperativity of burst phase reactions explored. J. Mol. Biol. 293, 1195–1210.
Kim P.S., Baldwin R.L. 1990. Intermediates in the folding reactions of small proteins. Annu. Rev. Biochem. 59, 631–666.
Clarke A.R., and Walto J.P. 1997. Protein folding pathways and intermediates. Curr. Opin. Biotechnol. 8, 400–410.
Roder H., Colon W. 1997. Kinetic role of early intermediates in protein folding. Curr. Opin. Struct. Biol. 7, 15–28.
Matouschek A., Kellis J.T., Jr., Serrano L., Fersht A.R. 1998. Mapping the transition state and pathway of protein folding by protein engineering. Nature. 340, 122–126.
Itzhaki L.S., Otzen D.E., Fersht A.R. 1995. The structure of the transition state for folding of Chymotrypsin Inhibitor 2 analyzed by protein engineering methods: Evidence for a nucleation-condensation mechanism for protein folding. J. Mol. Biol. 254, 260–288.
Matouschek A., Kellis J.T., Jr., Serrano L., Fersht A.R. 1990. Transient folding intermediates characterized by protein engineering. Nature. 346, 440–445.
Griko Yu.V., Privalov P.L., Venyaminov S.Yu., Kutyshenko V.P. 1988. Thermodynamic study of the apomyoglobin structure. J. Mol. Biol. 202, 127–138.
Jamin M., Antalik M., Loh S.N., Bolen D.W., Baldwin R.L. 2000. The unfolding enthalpy of the pH 4 molten globule of apomyoglobin measured by isothermal titration calorimetry. Protein Sci. 9, 1340–1346.
Hughson F.M., Wright P.E., Baldwin R.L. 1990. Structural characterization of a partly folded apomyoglobin intermediate. Science. 249, 1544–1548.
Jennings P.A., Wright P.E. 1993. Formation of a molten globule intermediate early in the kinetic folding pathway of apomyoglobin. Science. 262, 892–896.
Barrick D., Baldwin R.L. 1993. Three-state analysis of sperm whale apomyoglobin folding. Biochemistry. 32, 3790–3796.
Barrick D., Baldwin R.L. 1993. The molten globule intermediate of apomyoglobin and the process of protein folding. Protein Sci. 2, 869–876.
Eliezer D., Wright P.E. 1996. Is apomyoglobin a molten globule? Structural characterization by NMR. J. Mol. Biol. 263, 531–538.
Dolgikh D.A., Gilmanshin R.I., Brazhnikov E.V., Bychkova V.E., Semisotnov G.V., Venyaminov S.Yu., Ptitsyn O.B. 1981. Alpha-lactalbumin: Compact state with fluctuating tertiary structure? FEBS Lett. 136, 311–315.
Ptitsyn O.B. 1995. Molten globule and protein folding. Adv. Protein Chem. 47, 83–229.
Tsui V., Garcia C., Cavagnero S., Siuzdak G., Dyson H.J., Wright P.E. 1999. Quench-flow experiments combined with mass spectrometry show apomyoglobin folds through an obligatory intermediate. Protein Sci. 8, 45–49.
Baryshnikova E.N., Sharapov M.G., Kashparov I.A., Ilyina N.B., Bychkova V.E. 2005. Apomyoglobin stability as dependent on urea concentration and temperature at two pH values. Mol. Biol. 39, 330–335.
Jennings P.A., Stone M.J., Wright P.E. 1995. Overexpression of myoglobin and assignment of the amid, Cα and Cβ resonances. J. Biomol. NMR. 6, 271–276.
Harrison S.C., Blout E.R. 1965. Reversible conformational changes of myoglobin and apomyoglobin. J. Biol. Chem. 61, 623–627.
Pace C.N. 1986. Determination and analysis of urea and guanidine hydrochloride denaturation curves. Methods Enzymol. 131, 266–280.
Santoro M.M., Bolen D.W. 1988. Unfolding free energy changes determined by the linear extrapolation method: 1. Unfolding of phenylmethanesulfonyl alpha-chymotrypsin using different denaturants. Biochemistry. 27, 8063–8068.
Hargrove M.S., Krzywda S., Wilkinson A.J., Dou Y., Ikeda-Saito M., Olson J.S. 1994. Stability of myoglobin: A model for the folding of heme proteins. Biochemistry. 33, 11767–11775.
Ternstorm T., Mayor U., Akke M., Oliveberg M. 1999. From snapshot to movie: Φ-analysis of protein folding transition states taken one step further. Proc. Natl. Acad. Sci. USA. 96, 14854–14859.
Fersht A.R. 1985. Enzyme Structure and Mechanism, 2nd ed. N.Y.: W. H. Freeman.
Author information
Authors and Affiliations
Additional information
__________
Translated from Molekulyarnaya Biologiya, Vol. 39, No. 6, 2005, pp. 1008–1016.
Original Russian Text Copyright © 2005 by Baryshnikova, Melnik, Semisotnov, Bychkova.
Rights and permissions
About this article
Cite this article
Baryshnikova, E.N., Melnik, B.S., Semisotnov, G.V. et al. Folding/Unfolding Kinetics of Apomyoglobin. Mol Biol 39, 884–891 (2005). https://doi.org/10.1007/s11008-005-0109-6
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11008-005-0109-6