Rational design of enantioselective enzymes requires considerations of entropy

• Published in: Protein Science
• Main Authors: Ottosson, Jenny, Rotticci‐Mulder, Johanna C., Rotticci, Didier, Hult, Karl
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1110/ps.13501; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1110%2Fps.13501; https://onlinelibrary.wiley.com/doi/pdf/10.1110/ps.13501

Abstract 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 (Δ R‐S Δ H ‡ ) and entropy (Δ R‐S Δ S ‡ ) 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. Δ R‐S Δ S ‡ was in all cases equally significant as Δ R‐S Δ H ‡ 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 Δ R‐S Δ H ‡ and Δ R‐S Δ S ‡ . Although the changes in Δ R‐S Δ H ‡ and Δ R‐S Δ S ‡ were of a compensatory nature the compensation was not perfect, thereby allowing modifications of E. Both the W104H and the T103G variants displayed larger Δ R‐S Δ H ‡ than wild type but exhibited a decrease or increase, respectively, in E due to their different relative increase in Δ R‐S Δ S ‡ .