Water makes all the difference

Lars Schäfer investigates the details of the processes in cells with computer simulations. Water is a major driving force in the formation of separate reaction compartments within cells. In order to fulfil their function, biological cells need to be divided into separate reaction compartments. This is sometimes done with membranes, and sometimes without them: the spontaneous segregation of certain types of biomolecules leads to the formation of so-called condensates. Why and under which circumstances they form is currently being researched. Using computer simulations, Professor Lars Schäfer and Dr. Saumyak Mukherjee from the Center for Theoretical Chemistry at Ruhr University Bochum, Germany, have identified an often overlooked player: water. Because of their sheer numbers, the small water molecules are just as important as the large biomolecules in the molecular tug-of-war of the driving forces that underlie the formation of the condensates. The two researchers describe their findings in the journal Nature Communications , published on September 21, 2023. Densely packed scrum. It wasn't until recently that studies proved the existence of the condensates as reaction spaces in cells. "These condensates are incredibly densely packed, which means that there is a molecular scrum of biological macromolecules such as proteins and nucleic acids," explains Lars Schäfer. Since only certain macromolecules form such condensates with each other, they can act as specific microreactors for very specific biochemical reactions that take place in the cell. "It's therefore not surprising that disruptions in these processes are associated with various diseases," says Schäfer. David and Goliath. Why do these condensates form in the cell, and under what circumstances?