Carrie Arnold writes:

An elegant ballet of proteins enables modern cells to replicate themselves. During cell division, structural proteins and enzymes coordinate the duplication of DNA, the division of a cell’s cytoplasmic contents, and the cinching of the membrane that cleaves the cell. Getting these processes right is crucial because errors can lead to daughter cells that are abnormal or unviable.

Billions of years ago, the same challenge must have faced the first self-organizing membranous bundles of chemicals arising spontaneously from inanimate materials. But these protocells almost certainly had to replicate without relying on large proteins. How they did it is a key question for astrobiologists and biochemists studying the origins of life.

“If you delete all enzymes in the cell, nothing happens. They’re just inert sacks,” said Anna Wang, an astrobiologist at the University of New South Wales in Sydney. “They’re really stable, and that’s kind of the point.”

However, in a recent paper in Biophysical Journal, Romain Attal, a physicist at the City of Science and Industry in France, and the cancer biologist Laurent Schwartz of the Paris Public Hospitals developed a series of mathematical equations that model how heat alone could have been enough to drive one important part of the replication process: the fission of one protocell into two. [Continue reading…]