Compressibility as a means to detect and characterize globular protein states.

Chalikian, Tigran V.; Breslauer, Kenneth J.

doi:10.1073/pnas.93.3.1012

Cited by 78 publications

(61 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…18,65,66 This notion is in agreement with the roughly 2-fold increase in solvent accessible surface area of the protein accompanying its denaturation.…”

Section: ■ Resultssupporting

confidence: 73%

Interactions of Urea with Native and Unfolded Proteins: A Volumetric Study

et al. 2014

View full text Add to dashboard Cite

We describe a statistical thermodynamic approach to analyzing urea-dependent volumetric properties of proteins. We use this approach to analyze our urea-dependent data on the partial molar volume and adiabatic compressibility of lysozyme, apocytochrome c, ribonuclease A, and α-chymotrypsinogen A. The analysis produces the thermodynamic properties of elementary urea-protein association reactions while also yielding estimates of the effective solvent-accessible surface areas of the native and unfolded protein states. Lysozyme and apocytochrome c do not undergo urea-induced transitions. The former remains folded, while the latter is unfolded between 0 and 8 M urea. In contrast, ribonuclease A and α-chymotrypsinogen A exhibit urea-induced unfolding transitions. Thus, our data permit us to characterize urea-protein interactions in both the native and unfolded states. We interpreted the urea-dependent volumetric properties of the proteins in terms of the equilibrium constant, k, and changes in volume, ΔV0, and compressibility, ΔKT0, for a reaction in which urea binds to a protein with a concomitant release of two waters of hydration to the bulk. Comparison of the values of k, ΔV0, and ΔKT0 with the similar data obtained on small molecules mimicking protein groups reveals lack of cooperative effects involved in urea-protein interactions. In general, the volumetric approach, while providing a unique characterization of cosolvent-protein interactions, offers a practical way for evaluating the effective solvent accessible surface area of biologically significant fully or partially unfolded polypeptides.

show abstract

“…18,65,66 This notion is in agreement with the roughly 2-fold increase in solvent accessible surface area of the protein accompanying its denaturation.…”

Section: ■ Resultssupporting

confidence: 73%

Interactions of Urea with Native and Unfolded Proteins: A Volumetric Study

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Thus, the N-to-MG transitions of globular proteins studied to date are characterized by positive changes in compressibility. 25,26,59 In contrast to this notion, the N-to-MG pH4 (NaCl), N-to-MG pH2 (NaCl), and N-to-MG pH4 (NaTCA) transitions of apomyoglobin bring about negative changes in compressibility. This behavior is suggestive of the MG pH4 (NaCl), MG pH2 (NaCl), and MG pH4 (NaTCA) molten globule states of apomyoglobin being more extensively hydrated and less structured relative to other proteins capable of adopting a molten globule conformation (e.g., cytochrome c, -lactalbumin, -chymotrypsinogen A, etc.).…”

Section: Analysis Of Compressibility Datamentioning

confidence: 77%

“…26,59 Specifically, all native-to-molten globule (N-to-MG) transitions studied to date are accompanied by increases in k8 S ranging from 1 Â 10 À6 to 4 Â 10 À6 cm 3 g À1 bar À1 . Native-to-partially unfolded (N-to-PU) transitions are accompanied by small decreases in k8 S ranging from À3 Â 10 À6 to À7 Â 10 À6 cm 3 g À1 bar À1 .…”

Section: Analysis Of Compressibility Datamentioning

confidence: 99%

“…This behavior is suggestive of the MG pH4 (NaCl), MG pH2 (NaCl), and MG pH4 (NaTCA) molten globule states of apomyoglobin being more extensively hydrated and less structured relative to other proteins capable of adopting a molten globule conformation (e.g., cytochrome c, -lactalbumin, -chymotrypsinogen A, etc.). 25,26,59 Figure 3 shows the Dk S -vs.-dependence for an ''average'' globular protein with a molecular weight of 17 kDa calculated with Eq. (6).…”

Section: Analysis Of Compressibility Datamentioning

confidence: 99%

“…25,26,28,49,59 The hydration change in compressibility, Dk h , results from exposure to the solvent of previously buried atomic groups, as well as from the differential intensity of solute-solvent interactions in the native and denatured conformational states. 25,26 The intrinsic change in compressibility, k M , results from the change in the size of the solvent-inaccessible protein interior as well as in the packing of atomic groups within that interior.…”

Section: Analysis Of Compressibility Datamentioning

confidence: 99%

See 2 more Smart Citations

Compressibility changes accompanying conformational transitions of apomyoglobin

2005

View full text Add to dashboard Cite

We used high-precision density and ultrasonic velocity measurements to characterize the native (N), molten globule (MG), and unfolded (U) conformations of apomyoglobin. The molten globule states that were studied in this work include the MG(pH4)(NaCl) state observed at pH 4 and 20 mM NaCl, the MG(pH4)(NaTCA) state observed at pH 4 and 20 mM sodium trichloracetate (NaTCA), the MG(pH2)(NaCl) state observed at pH 2 and 200 mM NaCl, and the MG(pH2)(NaTCA) state observed at pH 2 and 20 mM NaTCA. We used our densimetric and acoustic data to evaluate changes in adiabatic compressibility associated with the acid- or salt-induced N-to-MG, MG-to-U, MG-to-MG, and U-to-MG transitions of the protein. The N-to-MG(pH4)(NaCl) and N-to-MG(pH4)(NaTCA) transitions are accompanied by decreases in compressibility of -(3.0 +/- 0.6) x 10(-6) and -(2.0 +/- 0.6) x 10(-6) cm3 g(-1)bar(-1), respectively. The N-to-MG(pH2)(NaCl) and N-to-MG(pH2)(NaTCA) transitions are associated with compressibility changes of -(4.9 +/- 1.1) x 10(-6) and (0.7 +/- 0.9) x 10(-6) cm3 g(-1) bar(-1), respectively. We interpret these data in terms of the degree of unfolding of the various molten globule forms of apomyoglobin. In general, our compressibility data reveal significant disparities between the various equilibrium molten globule states of apomyoglobin while also quantitatively characterizing each of these states. Volumetric insights provided by our data facilitate gaining a better understanding of the folding pathways, intermediates, and kinetics of apomyoglobin folding.

show abstract