Biological thermodynamic data for the calibration of differential scanning calorimeters: heat capacity data on the unfolding transition of ribonuclease a in solution

Schwarz, Frederick P.; Kirchhoff, William H.

doi:10.1016/0040-6031(88)85371-1

Cited by 46 publications

(32 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, On the other hand, net long-term drift in tempera-Origin data analysis software contains a Response butture is virtually zero when the shield is thermostatted. ton located on the graphic template, which when actiAlthough the improvements in adiabaticity consider-vated quickly removes small amounts of response-time ably reduce the long-term temperature drift when us-broadening for any of the four response times using ing the zero-scan-rate mode, it is still significant (Ç0.03 standard methods (2). This postrun capability somedeg/h at 65ЊC).…”

Section: Improvements In Adiabaticitymentioning

confidence: 97%

See 1 more Smart Citation

A New Ultrasensitive Scanning Calorimeter

Plotnikov¹,

Brandts²,

Lin³

et al. 1997

Analytical Biochemistry

164

View full text Add to dashboard Cite

Section: Improvements In Adiabaticitymentioning

confidence: 97%

“…Fax: 413-586-0149. 2 Abbreviation used: DSC, differential scanning calorimeter. ously during operation and stored in computer memory Corp.).…”

mentioning

confidence: 99%

A New Ultrasensitive Scanning Calorimeter

Plotnikov¹,

Brandts²,

Lin³

et al. 1997

Analytical Biochemistry

164

View full text Add to dashboard Cite

“…Differential Scanning Calorimetry-All DSC measurements were performed using a Hart 7707 DSC heat conduction scanning microcalorimeter as described by Schwarz and Kirchhoff (30). The Hart DSC consists of three removable vessels containing the protein solution and a fourth removable vessel containing just the buffer solution in an adiabatic enclosure.…”

Section: Methodsmentioning

confidence: 99%

The Structure of the T127L/S128A Mutant of cAMP Receptor Protein Facilitates Promoter Site Binding

Chu

Tordova

Gilliland

et al. 2001

Journal of Biological Chemistry

View full text Add to dashboard Cite

The x-ray crystal structure of the cAMP-ligated T127L/ S128A double mutant of cAMP receptor protein (CRP) was determined to a resolution of 2.2 Å. Although this structure is close to that of the x-ray crystal structure of cAMP-ligated CRP with one subunit in the open form and one subunit in the closed form, a bound syn-cAMP is clearly observed in the closed subunit in a third binding site in the C-terminal domain. In addition, water-mediated interactions replace the hydrogen bonding interactions between the N 6 of anticAMP bound in the N-terminal domains of each subunit and the OH groups of the Thr 127 and Ser 128 residues in the C ␣-helix of wild type CRP. This replacement induces flexibility in the C ␣-helix at Ala The allosteric protein cAMP receptor protein (CRP) 1 is activated by the binding of cAMP to enhance the transcription of over 25 genes, which code for enzymes involved in carbohydrate metabolism in Escherichia coli. The x-ray crystal structure of cAMP-ligated CRP consists of two 210-amino acid residue subunits, with the N-terminal domain of each subunit containing a central ␤-barrel connected to an ␣/␤ C-terminal domain via an ␣-helix, which also is the primary interface between the two subunits (1). The N-terminal regulatory domain ␤-strands form an eight-stranded ␤-barrel that binds anti-cAMP, and the Cterminal domain contains a helix-turn-helix motif followed by a small ␤-sheet that binds to the promoter site. One subunit (A) has a "closed" form, where the C-terminal domain is swung in toward the ␣-helical interface, and the other subunit (B) has an "open" form, where the C-terminal domain is swung away from the interface (1). In addition to interactions between the CRP binding site and the phosphate ribose of cAMP, Thr 127 at the ␣-helical interface forms a hydrogen bond with the N 6 of the bound cAMP, and Ser 128 forms a hydrogen bond with the bound cAMP in the other subunit (1). The nature of the conformational change to the allosterically activated conformation has not been determined because the x-ray crystal structure of unligated CRP is not known. Small angle neutron scattering measurements on unligated CRP solutions show that the data best fit the simulated scattering data from a minimized energy structure of CRP with both units in the open form (2). Minimum energy calculations starting with the x-ray structure of both anti-cAMP-ligated subunits in the closed form and both subunits in the open form in solution show that the minimum energy conformation of anti-cAMP-ligated CRP is with both subunits in the closed form (3). In NMR measurements, five sets of histidine resonances are observed for CRP alone and in its complexes with cyclic nucleotides, which also implies that both subunits are in the same conformation in solution (4). The x-ray structure of the cAMP-ligated complex of CRP bound to a 30-base pair DNA duplex, which has the same sequence as that of a promoter site, shows that both subunits are in the closed conformation (5, 6). The implication of these results is that the allost...

show abstract

“…It is also recommended that test solutions consisting of protein solutions that exhibit known transition enthalpies such as simple globular proteins like ribonuclease A [35], lysozyme [36], and lactoglobulin [37] be scanned to check the operating performance of the DSC. To evaluate the applicability of a protein test solution in checking the operating performance of different DSCs in different laboratories, samples of hen egg white lysozyme solutions were sent to six different international laboratories.…”

Section: Dsc Calibration and Test Proceduresmentioning

confidence: 99%

Measurement and analysis of results obtained on biological substances with differential scanning calorimetry (IUPAC Technical Report)

Hinz

Schwarz

2001

Pure and Applied Chemistry

View full text Add to dashboard Cite

Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgmentAbstract: Differential scanning calorimeters (DSCs) have been widely used to determine the thermodynamics of phase transitions and conformational changes in biological systems including proteins, nucleic acid sequences, and lipid assemblies. DSCs monitor the temperature difference between two vessels, one containing the biological solution and the other containing a reference solution, as a function of temperature at a given scan rate. Recommendations for DSC measurement procedures, calibration procedures, and procedures for testing the performance of the DSC are described. Analysis of the measurements should include a correction for the time response of the instrument and conversion of the power vs. time curve to a heat capacity vs. temperature plot. Thermodynamic transition models should only be applied to the analysis of the heat capacity curves if the model-derived transition temperatures and enthalpies are independent of the DSC scan rate. Otherwise, kinetic models should be applied to the analysis of the data. Application of thermodynamic transition models involving two states, two states and dissociation, and three states to the heat capacity vs. temperature data are described. To check the operating performance with standard DSCs, samples of 1 to 10 mg mL -1 solutions of hen egg white lysozyme in 0.1 M HCl-glycine buffer at pH = 2.4 ± 0.1 were sent to six different DSC laboratories worldwide. The values obtained from proper measurements and application of a two-state transition model yielded an average unfolding transition temperature for lysozyme of 331.2 K with values ranging from 329.4 to 331.9 K, and an average transition enthalpy of 405 kJ mol -1 with values ranging from 377 to 439 kJ mol -1 . It is recommended that the reporting of DSC results be specific with regard to the composition of the solution, the operating conditions and calibrations of the DSC, determination of base lines that may be model-dependent, and the model used in the analysis of the data.

show abstract

Biological thermodynamic data for the calibration of differential scanning calorimeters: heat capacity data on the unfolding transition of ribonuclease a in solution

Cited by 46 publications

References 16 publications

A New Ultrasensitive Scanning Calorimeter

A New Ultrasensitive Scanning Calorimeter

The Structure of the T127L/S128A Mutant of cAMP Receptor Protein Facilitates Promoter Site Binding

Measurement and analysis of results obtained on biological substances with differential scanning calorimetry (IUPAC Technical Report)

Contact Info

Product

Resources

About