In a study reported on August 31, MIT researchers found that three short peptides remained stable for many weeks in a solution of about 98 percent sulfuric acid and folded into loop shapes resembling the Greek letter omega. The work, published in the Proceedings of the National Academy of Sciences, used nuclear magnetic resonance spectroscopy in laboratory solutions meant to approximate Venus's acidic clouds, not samples from the planet.

The peptides studied were HHQ, a synthetic seven-amino-acid peptide; HHQ13, a longer variation; and K7, a seven-amino-acid peptide. In water, HHQ forms flat beta sheets that build into long fibrils, but in concentrated sulfuric acid it took a different shape. The researchers believe sulfuric acid molecules sit inside each loop as a scaffold holding the structure.

Mei Hong, an MIT chemistry professor and senior author, said the findings suggest peptides reaching Venus's cloud layer could be stably preserved there. Co-senior author Sara Seager said the results argue against ruling out non-Earth-like planets in the search for life. The authors say whether such folded peptides could perform biological functions is not known; the paper also reports plans to study longer peptides and double-stranded peptide nucleic acid. The research was funded by the Alfred P. Sloan Foundation, the NOMIS Foundation and the National Institutes of Health.