(27g) Polymer Motion Energizing Enzyme Conformational Dynamics and Catalytic Kinetics in Organic Solvents

Expanding the spectrum of enzymatic catalysis to chemical synthesis in non-aqueous solvents is often hindered by the low activity caused by the limited conformational dynamics of the enzyme. Here we propose an idea of energizing enzyme conformational dynamics thereby its catalytic kinetics in non-aqueous solvents by conjugating soluble polymer. For concept validation, we grafted triblock co-polymer Pluronic to Candida antarctica lipase B (CalB) forming Pluronic-CalB conjugates. We applied low-field nuclear magnetic resonance (LF-NMR) and molecular dynamics (MD) simulation to characterize enzyme conformational dynamics in acetonitrile, toluene and cyclohexane, respectively. LF-NMR conformed the enhancement conformational dynamics of CalB upon conjugating Pluronics, as interpreted from the extension of the transverse relaxation time of CalB. LF-NMR analysis also conformed the emerging effects of Pluronics on CalB conformational dynamics, which are conductive to an increase of CalB activity up to 2 orders of magnitude. MD showed that polymer conjugation expanded the enzyme conformational space and an improved preorganization of active sites, as compared with free CalB, both of which were favorable for an enhanced activity of the conjugated CalB in organic solvents. Above mentioned results provided new molecular and process insights of enzymatic catalysis in non-aqueous solvents.