Did disordered proteins help launch life on Earth?

Abstract

Four and a half billion years ago, our planet was a jagged, rocky landscape rich in minerals, swirling with carbon dioxide and other gases, and bombarded with meteorites. Somehow, around this time, the chemistry at work in this harsh environment yielded molecules that started to self-replicate. Thus began life on Earth. Most researchers studying early life believe that the first self-replicating molecule to take hold was RNA, an idea known as the RNA-world hypothesis. But eventually came proteins—the actors that carry out almost all cellular functions—and DNA, the blueprint that encodes them. It’s the proteins—and their building blocks, amino acids—that have always intrigued biochemist A. Keith Dunker, an emeritus professor at Indiana University. He knew that researchers had long speculated that the early genetic code was much simpler than it is today, perhaps just 2 or 3 DNA nucleotides coding for 12 or 14 amino acids rather than today’s canonical