Denaturation apomyoglobin

Results from the acidic denaturation of myoglobin as a function of the time. Three species are observed native hMb (heme + myoglobin), denaturated hMb (heme + denaturated hemoglobin) and denaturated aMb (denaturated apomyoglobin). Reproduced (modified) from Konermann L., Rosell F.I., Mauk A.G. and Douglas D.J., Biochemistry, 34, 5554-5559,1997, with permission. 

DeYoung, L.R., K.A. Dill, and A.L. Fink. 1993. Aggregation and denaturation of apomyoglobin in aqueous urea solutions. Biochemistry 32 3877-3886. 

The thermal stability of metmyoglobin and apomyoglobin has been extensively studied under different solvent conditions (Privalov et al., 1986). In particular, it was shown that at low pH values both the heat and cold denaturation peaks are clearly visible in the calorimetric scans. Figure 10 shows the excess heat capacity function for apomyoglobin predicted by the hierarchical partition function and the thermodynamic parameters described above. In order to simulate the experimental curve obtained at pH 3.83 (Privalov et al., 1986), the protonation of five specific histidine residues on unfolding was... 

Yang, A. and B. Honig. (1994). Structural origins of pH and ionic strength effects on protein stability. Acid denaturation of sperm whale apomyoglobin. J. Mol. Biol. 237 602-14. 

Data of Nigen et ai, 1973a, Proton decoupled, natural abundance 3C FTnmr spectra of modified harbor seal apomyoglobin obtained on a home built spectrometer at 15 08 MHz and 33-35° on 8 mM denatured harbor seal apomyoglobin prepared by carboxymethylation in the presence of 8 M urea, pH = 6 89, Chemical shifts corrected to TMS scale using 6CS. = 193 7 ppm. 

Combination of fluorescence resonance energy transfer with stopped flow experiments helped to resolve submillisecond events in die folding of ACBP, This approaeh has allowed the eharaeterization of the kinetics and stability of a transient intermediate populated on the 100-ps time seale. Thus, intermediate states between native and totally denatured do exists in ACBP as it is observed for other proteins sueh as apomyoglobin. 

Strength Effects on Protein Stability—Acid Denaturation of Sperm Whale Apomyoglobin. 

A.-S. Yang and B. Honig, /. Mol. Biol., 237, 602 (1994). Structural Origins of pH and Ionic Strength Effects on Protein Stability. Acid Denaturation of Sperm WTiale Apomyoglobin. 

We conclude this discussion with some recent data on denaturation and refolding of sperm whale myoglobin and apomyoglobin (Shen and Hermans (76)). Kinetic data on the refolding of this protein are potentially extremely valuable because a) the conformation of myoglobin is known, and b) the unfolding equilibrium is particularly well understood (34). The equilibrium follows a two state description, and, furthermore, free... 

Figure 6.21 (a) Kratky plot recorded with urea-denatured (unfolded) apomyoglobin in buffer solution at pH 6.0. Adapted with permission from Ref [73] 2007, American Chemical Society (b) Schematic... 

Figure 9.16. Denaturation of holomyoglobin (hMb) in water/ methanol (75 25 v/v) at pH 11.2 monitored by time-resolved ESI MS in the negative-ion mode. These spectra were recorded 0.08 s (A), 0.43 s (B), 1.2 s (C), and 5 min (D) after initiation of denaturation. Notation h is tiMb a is apomyoglobin (aMb), H is heme. Also indicated are the charge stales of some protein ions. (Reprinted with permission from Sogbein, O. Simmons, D. A. Konermann, L. J. Am. Soc. Mass Spectrom. 2000, //, 312-319.)...

A. N. McCarthy and J. R. Grigera, Biochim. Biophys. Acta, 1764, 506 (2006). Pressure Denaturation of Apomyoglobin A Molecular Dynamics Simulation Study. 

Barrick, D., Hughson, F.M., and Baldwin, R.L., 1994, Molecular mechanisms of acid denaturation - the role of histidine residues in the partial unfolding of apomyoglobin, J. Mol Biol. 237 588-601. 

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