Increasing and decreasing protein stability: Effects of revertant substitutions on the thermal denaturation of phage λ repressor
✍ Scribed by Michael H. Hecht; Kathleen M. Hehir; Hillary C. M. Nelson; Julian M. Sturtevant; Robert T. Sauer
- Publisher
- John Wiley and Sons
- Year
- 1985
- Tongue
- English
- Weight
- 440 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
The thermal denaturations of five revertant h repressors containing single amino acid substitutions in their N-terminal domains have been studied by differential scanning calorimetry. Two substitutions slightly decrease stability, and the remaining three render the protein more stable than wild type. The G1y48-+Asn and GIy4X+Ser proteins are 4°C more stable than wild type. These two substitutions replace an Q! helical'residue, and in each case a poor helix forming residue, glycine, is replaced by a residue with a higher helical propensity. We also present data showing that one revertant, Tyr22+Phe, has reduced operator DNA binding affinity despite its enhanced stability.