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Aqueous Droplets Used as Enzymatic Microreactors and Their Electromagnetic Actuation
Published on: August 28, 2017
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How Droplets Can Accelerate Reactions─Coacervate Protocells as Catalytic Microcompartments
Iris B A Smokers1, Brent S Visser1, Annemiek D Slootbeek1
1Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6523 AJ Nijmegen, The Netherlands.
Accounts of Chemical Research
|July 5, 2024
Summary
Coacervates, model protocells, accelerate prebiotic reactions by altering local environments and concentrating reactants. These liquid-liquid phase separation droplets enhance reaction rates and selectivity, crucial for the origin of life and modern cellular processes.
Area of Science:
- Origin of Life Studies
- Biochemistry
- Chemical Biology
Background:
- Coacervates are droplets formed via liquid-liquid phase separation (LLPS), serving as model protocells.
- They are relevant to the origin of life and exist as membraneless organelles in modern cells.
- The internal environment of coacervates differs significantly from the surrounding solution, offering unique microenvironments for reactions.
Purpose of the Study:
- To dissect the mechanisms by which coacervate protocells accelerate reactions and provide selectivity.
- To explore how coacervates function as enzyme-like catalytic microcompartments.
- To illustrate how these mechanisms can be exploited by membraneless organelles.
Main Methods:
- Analysis of coacervate properties influencing reaction rates and selectivity.
- Investigation of reactant concentration, stabilization, and transition state modulation.
- Examination of the impact of the coacervate's physicochemical environment (polarity, charge, crowding, water activity) on reactions.
- Case study on ribozyme reactions within coacervates.
Main Results:
- Coacervates accelerate reactions by altering reactant concentrations (copartitioning or exclusion).
- The internal environment modulates reaction energy landscapes, affecting reactant, transition state, and product stability.
- Coacervates facilitate reactions sensitive to pH, water activity, and hydrolysis, and can localize catalysts.
- Coacervate properties favor specific reaction pathways, leading to selectivity in reaction outcomes.
- Coacervates were shown to catalyze ribozyme reactions and provide product selectivity.
Conclusions:
- Coacervate protocells offer mechanisms for rate enhancement and selectivity essential for the origin of life.
- These properties enable coacervates to function as primitive enzyme-like catalysts.
- The principles governing coacervate-mediated reactions are applicable to understanding membraneless organelles in modern cells.
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