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Rational design of ...
Abstract
Ämnesord
Stäng
- Entropy was shown to play an equally important role as enthalpy for how enantioselectivity changes when redesigning an enzyme. By studying the temperature dependence of the enantiomeric ratio E of an enantioselective enzyme, its differential activation enthalpy (Delta (R-S)DeltaH(double dagger)) and entropy (Delta (R-S)DeltaS(double dagger)) components can be determined. This was done for the resolution of 3-methyl-2-butanol catalyzed by Candida antarctica lipase B and five variants with one or two point mutations. Delta (R-S)DeltaS(double dagger) was in all cases equally significant as Delta (R-S)DeltaH(double dagger) to E. One variant, T103G, displayed an increase in E, the others a decrease. The altered enantioselectivities of the variants were all related to simultaneous changes in Delta (R-S)DeltaH(double dagger) and Delta (R-S)DeltaS(double dagger). Although the changes in Delta (R-S)DeltaH(double dagger) and Delta (R-S)DeltaS(double dagger) were of a compensatory nature the compensation was not perfect, thereby allowing modifications of E. Both the W104H and the T103G variants displayed larger Delta (R-S)DeltaH(double dagger). than wild type but exhibited a decrease or increase, respectively, in E due to their different relative increase in Delta (R-S)DeltaS(double dagger).
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Industriell bioteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Industrial Biotechnology (hsv//eng)
Nyckelord
- enthalpy; entropy; enantiomeric ratio; lipase; Candida antarctica; site-directed mutagenesis
- Bioengineering
- Bioteknik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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