Miniature water droplets could solve an origin of life riddle

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Miniature water droplets could solve an origin of life riddle

Life on Earth could not have begun without water. Even water prevents some chemical reactions necessary for life itself.

Miniature droplets of water

Researchers found a novel solution to the water problem in the form of miniature droplets of water, formed during a crashing ocean wave or the clouds in the sky. The water problem relates primarily to the element phosphorous, which attach to a variety of life’s molecules through a process called phosphorylation.

Phosphorous, a necessary ingredient in many molecules critical for life, including our DNA. DNA and RNA that make up our body’s energy storage system, called ATP. But, ordinary water gets in the way of producing those chemicals.

Modern life has evolved ways of sidestepping that problem in the form of enzymes that help phosphorylation along. But, how primitive components of these molecules formed before the workarounds evolved remains a controversial and at times slightly oddball subject.

Phosphorylation

Microdroplets solve the phosphorylation problem in a relatively elegant way in large part because they have geometry on their side. Microdroplets are mostly surface. They perfectly optimize the need for life to form in and around water. But, with enough surface area for phosphorylation and other reactions to occur.

However, microdroplets provide a large amount of surface area. Previous experiments suggest microdroplets can increase reaction rates for other processes by a thousand or even a million times, depending on the details of the reaction being studied.

Microdroplets seemed like a possible solution to the water problem. But, researchers sprayed tiny droplets of water with phosphorous, and other chemicals into a chamber. They found several phosphate-containing molecules occurred spontaneously on these lab-made microdroplets without any catalyst to get they started.

Those molecules included sugar phosphates, which are a step in how our cells create energy, and one of the molecules that make up RNA. Finally, both reactions are rare at best in larger volumes of water.

That observation, joined with the fact that microdroplets are ubiquitous from clouds in the sky to the mist created by a crashing ocean wave suggests that they could have played a role in fostering life on Earth. In the future, researchers hope to look for phosphates that make up proteins and other molecules.

More information: [Stanford University]