Extraterrestrial phosphorus species brought to Earth by comets and meteorites may have played a key role in the origins of life on our planet, claim UK researchers. 

Terence Kee at the University of Leeds and colleagues made phosponates (closely related to phosphates) under simulated outer-space conditions.

Kee's team combined experiments with computer simulations to study phosphorus-containing compounds that are only found naturally in space. The researchers showed that hydrolysis of interstellar phosphorus molecules, in the absence of oxygen, could have been a source of so-called Murchison-type phosponates (those found in a meteorite that fell near Murchison, Australia, in 1969). 

Phosphorus plays a vital role in cell physiology and biochemistry - it is found in biomolecules such as nucleic acids, phospholipids, proteins and polysaccharides. But as the most common form of phosphorus present on Earth today (phosphate) has low solubility in water, its use in our early chemistry is difficult to explain.

The discovery of the Murchison-type phosponates had suggested that prebiotic chemistry may have been based around phosphorus in oxidation states lower than that found in current biological molecules. This was the first convincing evidence of water-soluble phosphorus species brought to Earth by comets and meteorites.  How these organic molecules could have been formed in space had previously remained unexplained, until now.

Kee said linking these phosphonates to biological systems, through pre-biotic chemistry, could 'have the potential to influence the way we think about how life developed on Earth and may have developed elsewhere in the universe.'

Debora Giovanelli