Differential scanning calorimetry study of the thermodynamic stability of some mutants of Sso7d from Sulfolobus solfataricus.


Abstract

Sso7d from the thermoacidophilic archaebacterium Sulfolobus solfataricus is a small globular protein with a known three-dimensional structure. Inspection of the structure reveals that Phe31 is a member of the aromatic cluster forming the protein hydrophobic core, whereas Trp23 is located on the protein surface and its side chain exposed to the solvent. The thermodynamic consequences of the substitution of these two residues in Sso7d have been investigated by comparing the temperature-induced denaturation of Sso7d with that of three mutants: F31A-Sso7d, F31Y-Sso7d, and W23A-Sso7d. The denaturation processes proved to be reversible for all proteins, and represented well by the two-state N if D transition model in a wide range of pH. All three mutants are less thermally stable than the parent protein; in particular, in the pH range of 5.0-7.0, the F31A substitution leads to a decrease of 24 degreesC in the denaturation temperature, the F31Y substitution to a decrease of 10 degreesC, and the W23A substitution to a decrease of 6 degreesC. A careful thermodynamic analysis of such experimental data is carried out. Study holds ProTherm entries: 9453 Extra Details: thermoacidophilic; aromatic cluster; hydrophobic core;,thermodynamic analysis

Submission Details

ID: gBs7QicC3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:38 p.m.

Version: 1

Publication Details
Catanzano F;Graziano G;Fusi P;Tortora P;Barone G,Biochemistry (1998) Differential scanning calorimetry study of the thermodynamic stability of some mutants of Sso7d from Sulfolobus solfataricus. PMID:9671520
Additional Information

Sequence Assay Result Units