Patterns of nonadditivity between pairs of stability mutations in staphylococcal nuclease
| Autor: | David Shortle, Susan M. Green |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Delta
Protein Denaturation Stereochemistry Mutant DNA Recombinant medicine.disease_cause Guanidines Biochemistry Protein Structure Secondary chemistry.chemical_compound Additive function Enzyme Stability medicine Micrococcal Nuclease Denaturation (biochemistry) Amino Acid Sequence Guanidine chemistry.chemical_classification Nuclease Mutation biology Recombinant Proteins Amino acid Models Structural chemistry Mutagenesis Site-Directed biology.protein |
| Zdroj: | Biochemistry. 32:10131-10139 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi00089a032 |
| Popis: | To identify interactions between amino acid positions in staphylococcal nuclease that affect its stability, a collection of 71 double-mutant forms was constructed from 22 previously characterized single mutants. These single mutations were assigned to three different classes on the basis of their m value [m = d(delta G)/d[GuHCl]], a parameter that has been correlated with energetically significant changes in the structure of the denatured state [Green et al. (1992) Biochemistry 31,5717-5728]. Several mutant pairs from five of the six possible double-mutant classes were analyzed by guanidine hydrochloride denaturation to determine the extent to which changes in stability (delta delta GH2O) and changes in the m value (delta mGuHCl) reflect the sum of the effects of the individual mutants. The differences between the values for delta delta GH2O and delta mGuHCl estimated on the assumption of additivity and those obtained by experiment, i.e., delta delta delta G and delta delta m, were calculated for each double-mutant protein. Surprisingly, a large majority of double mutants from four of the five classes exhibited positive values of delta delta delta G and delta delta m; i.e., they were more stable and displayed a higher sensitivity to GuHCl than predicted on the basis of additivity.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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