Both carbon monoxide and cyanide are highly poisonous to human beings. However, a group of researchers from Boise State University and NASA have discovered compounds in meteorites containing iron, cyanide and carbon monoxide, which may have been helpful in the beginning of life on Earth. The compounds which are found in meteorites are quite similar to the active site of hydrogenases, the enzymes which provide energy to bacteria by decomposition of hydrogen gas. The results present the conclusion that these compounds were also there on early stages of Earth before the initiation of life. In this time period, several meteorites crashed onto Earth and there was a greater percentage of hydrogen in the atmosphere.
Dr. Karen Smith, a senior researcher at the Boise State University explained that most people think of cyanide as a compound which instantly kills a person if consumed but on the other hand, it was an important compound for the formation of life on Earth. Cyanide consists of a carbon atom bound to nitrogen and it is an important participant in the non-biological synthesis of compounds such as amino acids and nucleobases. These are the building blocks of proteins, nucleic acids that are used by all life forms. The study is published in Nature Communications.
Smith along with Mike Callahan, a co-author of the paper created analytical methods for extracting and calculating the traces of cyanide present in the meteorites. They saw that the cyanide belonged to a group of carbon-rich meteorites known as CM chondrites. In other types of meteorites, no cyanide was found. Jason Dworkin of Goddard Space Flight Centre of NASA said that according to the data collected by OSIRIS-REx spacecraft of Bennu asteroid, the cyanides are from CM chondrites. A sample of this asteroid will be delivered to Earth in 2023 by the spacecraft. Researchers will then search for the compounds for drawing a relation of Bennu with the known meteorites and also understand how compounds such as cyanide got delivered to Earth.
Although cyanide was found before in meteorites, scientists were surprised to find a bonding of cyanide and carbon monoxide with iron for the formation of stable compounds in meteorites. Two different kinds of iron cyano-carbonyl complexes were found in the meteorites with the help of liquid chromatography-mass spectrometry.
Hydrogenases are present in almost all types of modern bacteria. They are huge proteins but the active site is a very small metal organic compound present in the protein. The similarities between the active site of hydrogenases and cyanide compounds could be a possible explanation of the origin of life from non-biological chemical processes.