Scientists recently took another step forward in determining how life got its start on Earth. Researchers at The Scripps Research Institute and the Salk Institute for Biological Studies have been experimenting with a component of volcanic gas to see if it played a role in amino acids forming the first peptides:
“There are lots of ways to make amino acids,” says Professor M. Reza Ghadiri, Ph.D., who is a member of The Skaggs Institute for Chemical Biology at Scripps Research. “But the question is, how do you couple them together?”
Ghadiri and Luke Leman, who is a member of the Kellogg School of Science and Technology at Scripps Research, worked out one possible solution with Leslie Orgel of the Salk Institute. In the latest issue of the journal Science, Leman, Ghadiri, and Orgel suggest that the missing link is a chemical component of volcanic gas known as carbonyl sulfide.
Carbonyl sulfide is present in volcanic gasses and deep sea vent emissions today, and since these geological phenomena were prominent features on the early Earth, it is reasonable to assume that the gas was present.
In their report, the scientists demonstrate that the gas can bring about a vigorous chemical reaction that forms peptides under mild aqueous conditions. Within a few minutes of introducing the gas to a reaction vessel containing amino acids, they observed high yields of di-, tri-, and tetra-peptides. They carried out the reaction in the presence of air, without air, and with and without other ingredients like metal ions, and they found peptides formed readily under all these conditions.
“It’s really efficient, actually,” says Ghadiri. “This addresses a very important question that we did not have a real good answer for.”
The scientists are quick to caution that there is still much work to be done before the full answer to the riddle of how life originated is known, but they also insist that it is far from an insoluble problem. This advance opens up new avenues to explore and the team plans to experiment further with carbonyl sulfide to see if it may play a part in other chemical reactions that would be involved in prebiotic chemistry.