Premium
Increasing and decreasing protein stability: Effects of revertant substitutions on the thermal denaturation of phage λ repressor
Author(s) -
Hecht Michael H.,
Hehir Kathleen M.,
Nelson Hillary C. M.,
Sturtevant Julian M.,
Sauer Robert T.
Publication year - 1985
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240290306
Subject(s) - residue (chemistry) , repressor , alanine , thermal stability , chemistry , dna , amino acid , denaturation (fissile materials) , amino acid residue , circular dichroism , differential scanning calorimetry , wild type , helix (gastropod) , glycine , stereochemistry , biochemistry , peptide sequence , biology , gene , transcription factor , ecology , physics , organic chemistry , nuclear chemistry , snail , thermodynamics , mutant
The thermal denaturations of five revertant λ 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 Gly 48 → Asn and Gly 48 → Ser proteins are 4°C more stable than wild type. These two substitutions replace an α 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, Tyr 22 → Phe, has reduced operator DNA binding affinity despite its enhanced stability.