Cysteine synthesis was a key step in the origin of life

In an important step during the early evolution of life on Earth, the formation of the amino acid cysteine delivered vital catalysts, which enabled the earliest protein molecules to form in water, according to a new study by UCL researchers. All proteins are built from the same 20 amino acids. One of these, cysteine, was assumed not to have been present at the origin of life. Despite its fundamental importance to all life today, it was unclear how cysteine might have formed on the early Earth. In a new study, published in Science , UCL scientists have recreated how cysteine was formed at the origins of life. Additionally, they have observed how, once formed, cysteine catalyses the fusion of peptides in water - a fundamental step in the path towards protein enzymes. The UCL researchers created cysteine using very simple chemistry and chemicals - hydrogen cyanide and hydrogen sulfide - that were likely to be abundant on the early Earth.