Active coacervate droplets are protocells that grow and resist Ostwald ripening

TY - JOUR

T1 - Active coacervate droplets are protocells that grow and resist Ostwald ripening

AU - Nakashima, Karina K

AU - van Haren, Merlijn H I

AU - André, Alain A M

AU - Robu, Irina

AU - Spruijt, Evan

PY - 2021/12/1

Y1 - 2021/12/1

N2 - Active coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions and translational entropy within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.

AB - Active coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions and translational entropy within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.

KW - Adenosine Diphosphate/metabolism

KW - Adenosine Triphosphate/chemistry

KW - Artificial Cells/chemistry

KW - Cell Growth Processes

KW - Elastin/chemistry

KW - Peptides/chemistry

KW - Phosphoenolpyruvate/metabolism

KW - Pyruvate Kinase/metabolism

UR - http://www.scopus.com/inward/record.url?scp=85108431509&partnerID=8YFLogxK

U2 - 10.1038/s41467-021-24111-x

DO - 10.1038/s41467-021-24111-x

M3 - Journal article

C2 - 34155210

SN - 2041-1723

VL - 12

SP - 3819

JO - Nature Communications

JF - Nature Communications

IS - 1

M1 - 3819

ER -