The Thermal Transition of Ribonuclease in Urea Solutions

Foss, John G.; Schellman, John A.

doi:10.1021/j150582a007

Cited by 65 publications

(26 citation statements)

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“…Similar decreases in the Tm have been observed when chymotrypsin is exposed to urea or alcohol (15,36,114,118) The fact that these two rates are similar suggests that a tryptophan . residue may be essential for the maintenance of enzyme activity.…”

Section: Solubility Mullaney and Preissmentioning

confidence: 57%

Conformational Changes in Several Enzymes During Photodynamic Inactivation.

Hopkins¹

1967

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Section: Solubility Mullaney and Preissmentioning

confidence: 57%

Conformational Changes in Several Enzymes During Photodynamic Inactivation.

Hopkins¹

1967

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“…These results are illustrated in Figure 3. The small rise on the low temperature side of some of the curves is due to an "inverted transition," discussed by Foss and Schellman (1959). It is the sharp decrease on the high temperature side of each of these curves which is characteristic of the normal transition under discussion here.…”

Section: A Ureamentioning

confidence: 67%

“…In fact, the high temperature condition was used in the preparative procedure in order to denature nonribonuclease components. (Foss and Schellman, 1959). was near 6OOC.…”

Section: A Ureamentioning

confidence: 95%

“…(Buzzell and Tanford, 1956) we may conclude that the molecular size and shape are pH independent over this range. Foss and Ryerson (1958) carried out measurements of the sorption of water vapor by lyophilixed ribonuclease and concluded that many of the polar sites of the peptide backbone are not available to water vapor because of the folding of the protein.…”

Section: I78 Iiaizold a Scheh%ga A K D J O H S A Kupleimentioning

confidence: 99%

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Structure and Function of Ribonuclease

Scheraga

Rupley

1962

Advances in Enzymology - And Related Areas of Molecular Biology

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“…4; Table 2). Perturbation of T, with denaturant has been suggested in the past (Foss & Schellman, 1959 Following the procedure described by Makhatadze and Privalov (1992), the AH,,u, contribution can be expressed as:…”

Section: Discussionmentioning

confidence: 99%

Conformational stability of HPr: The histidine‐containing phosphocarrier protein from Bacillus subtilis

Scholtz

1995

Protein Science

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The conformational stability of the histidine-containing phosphocarrier protein (HPr) from Bacillus subtilis has been determined using a combination of thermal unfolding and solvent denaturation experiments. The urea-induced denaturation of HPr was monitored spectroscopically at fixed temperatures and thermal unfolding was performed in the presence of fixed concentrations of urea. These data were analyzed in several different ways to afford a measure of the cardinal parameters (AH,, Tg, AS,, and AC,) that describe the thermodynamics of folding for HPr. The method of Pace and Laurents (Pace CN, Laurents DV, 1989, Biochemistry 28:2520-2525) was used to estimate AC, as was a global analysis of the thermal-and urea-induced unfolding data. Each method used to analyze the data gives a similar value for AC, (1,170 * 50 cal mol" K"). Despite the high melting temperature for HPr (T, = 73.5 "C), the maximum stability of the protein, which occurs at 26 "C, is quite modest (AGs = 4.2 kcal mol"). In the presence of moderate concentrations of urea, HPr exhibits cold denaturation, and thus a complete stability curve for HPr, including a measure of AC,, can be achieved using the method of Chen and Schellman (Chen B, Schellman JA, 1989, Biochemistry 28:685-691). A comparison of the different methods for the analysis of solvent denaturation curves is provided and the effects of urea on the thermal stability of this small giobular protein are discussed. The methods presented will be of general utility in the characterization of the stability curve for many small proteins. Keywords: cold denaturation; conformational stability; protein foldingA complete thermodynamic description of the stability of globular proteins is crucial to our understanding of the energetics of protein structure, folding, and function. Here we describe the complete stability curve, the variation of the Gibbs energy of folding with temperature, for histidine-containing phosphocarrier protein (HPr) using a combination of thermal-and ureainduced unfolding experiments and spectroscopic probes for the folding transition. The data have been analyzed in several ways to afford measures of the cardinal thermodynamic parameters (AH,, AS,, T,, etc., evaluated at the temperature where A G = 0; see Becktel & Schellman, 1987) necessary for a description of the conformational stability of HPr. Included in the analysis is the assumption that AC, is temperature independent and that the denatured forms of HPr at high temperature or in the presence of high concentrations of urea are thermodynamically inReprint requests to: .I.

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The Thermal Transition of Ribonuclease in Urea Solutions

Cited by 65 publications

References 0 publications

Conformational Changes in Several Enzymes During Photodynamic Inactivation.

Conformational Changes in Several Enzymes During Photodynamic Inactivation.

Structure and Function of Ribonuclease

Conformational stability of HPr: The histidine‐containing phosphocarrier protein from Bacillus subtilis

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