It could be called the search for the origin of life, but instead of a sweeping theory (primordial soup and lightning), microbiologists are concentrating on the many pieces that, one way or another, came together to constitute ‘life.’ Some new research from a team at the University of Colorado (Boulder, USA) points to the smallest RNA enzyme ever known to produce a chemical reaction within a cell. Most cells have RNA with thousands of genetic units (nucleotides), but the research called for something simple: a ribozyme, a form of RNA that catalyzes chemical reactions, but has only five nucleotides.
It’s reasoned that a chemical compounds began reaching ‘proto-life’ conditions, one of the first of the more complex organic compounds was probably a ribozyme, or something very much like it. The question was, “How could something this basic – only five nucleotides – produce a chemical reaction typical of an enzyme?” But it does. The experimental work with RNA ribozyme showed that it does, indeed, produce reactions.
Here’s what Professor Michael Yarus (University of Colorado) found as the key point:
Yarus noted that the RNA World hypothesis was complicated by the fact that RNA molecules are hard to make. “This work shows that RNA enzymes could have been far smaller, and therefore far easier to make under primitive conditions, than anyone has expected.”
If very simple RNA molecules such as the product of the Yarus lab could have accelerated chemical reactions in Earth’s primordial stew, the chances are much greater that RNA could direct and accelerate biochemical reactions under primitive conditions.
Before the advent of RNA, most biologists believe, there was a simpler world of chemical replicators that could only make more of themselves, given the raw materials of the time, Yarus said.
“If there exists that kind of mini-catalyst, a ‘sister’ to the one we describe, the world of the replicators would also jump a long step closer and we could really feel we were closing in on the first things on Earth that could undergo Darwinian evolution,” Yarus said.
Keep in mind that the researchers are not saying they have the ‘original’ ribozyme, only that a ribozyme-like enzyme – and early form of RNA – was very likely a component of the many compounds necessary to produce a self-replicating entity (a.k.a. life). Nevertheless, this is an important step in the direction that will eventually lead to the creation of the necessary components.