Kramers’ Theory and the Dependence of Enzyme Dynamics on Trehalose-Mediated Viscosity

Abstract

The disaccharide trehalose is accumulated in the cytoplasm of some organisms in response to harsh environmental conditions. Trehalose biosynthesis and accumulation are important for the survival of such organisms by protecting the structure and function of proteins and membranes. Trehalose affects the dynamics of proteins and water molecules in the bulk and the protein hydration shell. Enzyme catalysis and other processes dependent on protein dynamics are affected by the viscosity generated by trehalose, as described by the Kramers’ theory of rate reactions. Enzyme/protein stabilization by trehalose against thermal inactivation/unfolding is also explained by the viscosity mediated hindering of the thermally generated structural dynamics, as described by Kramers’ theory. The analysis of the relationship of viscosity–protein dynamics, and its effects on enzyme/protein function and other processes (thermal inactivation and unfolding/folding), is the focus of the present work regarding the disaccharide trehalose as the viscosity generating solute. Finally, trehalose is widely used (alone or in combination with other compounds) in the stabilization of enzymes in the laboratory and in biotechnological applications; hence, considering the effect of viscosity on catalysis and stability of enzymes may help to improve the results of trehalose in its diverse uses/applications.

Pushing the boundaries of phosphorylase cascade reaction for cellobiose production II: Model‐based multiobjective optimization

“…Effect of the reactant concentration (Figure 4a) can also be expressed in terms of change of microviscosity caused, as shown in Supporting Information: Figure S5. Plausible interpretation of the viscosity effect is according to Kramer's theory: the transmission coefficient for virtual barrier crossing in the rate‐limiting step of the overall CbP catalysis ( k cat ) depends inversely on the solvent friction (Sampedro et al, 2020). On this interpretation, an empirical extension of model M4 was made to express dependence of the maximum rate of CbP on the total reactant concentration present in the reaction, relative to the reference of the enzyme's maximum rate under standard assay conditions (total reactant concentration: 27.4 g/L).…”

“…A prominent way for high sugar concentrations to influence enzyme activity is through their effect on bulk microviscosity. Physical steps of enzyme catalysis, in particular those involving dynamical rearrangements of the protein structure, can be sensitive to changes in the microviscosity (Sampedro et al, 2020). We here performed initial rate experiments using α,α-trehalose as a small-molecule microviscogen that is unreactive with both CbP and ScP.…”

The Human Paraoxonase 2: An Optimized Procedure for Refolding and Stabilization Facilitates Enzyme Analyses and a Proteomics Approach

“…Moreover, at a higher concentration of glycerol, the protein residual activity was reduced, compared to lower concentrations. High concentrations of viscosity-generating solutes can affect the enzyme s Michaelis-Menten constant [40][41][42], therefore affecting the catalytic efficiency [42,43]. However, the effect of glycerol was different when samples of rPON2 were stored in 20% glycerol at −20 °C.…”

The breaking of fungal spore dormancy: A coordinated transition

“…The spore's cytoplasm containing high trehalose concentrations has been described as a "glassy state" where molecules, in particular proteins, are no longer freely moving [4]. This state causes proteins to be nonflexible and could affect proper folding of proteins [5]. As such, enzymes, although preserved, are thought to be mostly inactive when inside this glassy state.…”