Kiralne molekule jesu molekule koje ne mogu biti prevedene u svoju zrcalnu sliku. Uobičajeni su primjer za ove molekule organske molekule u kojima se nalazi asimetrično građeni ugljikov atom, tj. ugljikov atom na koji su vezana četiri različita atoma ili atomske grupe. Kiralne molekule razlikuju se jedino u optičkoj aktivnosti. Jedan izomer zakreće ravninu polariziranog svjetla u lijevo a drugi u desno. Smjesa jednakih dijelova lijevog i desnog izomera naziva se racemat.
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First mirror image molecule spotted in interstellar space
And though it isn’t directly involved in biochemical reactions, it may shed light on how the chiral molecules that ultimately led to life on Earth formed in the first place.
Asymmetric molecule, key to life, detected in space for first timeA variety of substances, including simple carbon-bearing molecules thought to be important precursors for life, have been spotted in interstellar space around nearby stars. But the team’s new finding of a chiral molecule “offer[s] another step of complexity” that suggests that other such substances, including prebiotic molecules, can form in interstellar space, possibly on the surfaces of small grains of ice, says Tom Millar, an astrochemist at Queen’s University Belfast in the United Kingdom, who was not involved in the work. The findings also open up challenges for other teams to further study how life’s earliest ingredients might have formed, he notes.
Scientists for the first time have found a complex organic molecule in space that bears the same asymmetric structure as molecules that are key to life on Earth.
Scientists just got one step closer to answering one of biology’s greatest mysteries"It is a pioneering leap forward in our understanding of how prebiotic molecules are made in the universe and the effects they may have on the origins of life," chemist Brett McGuire of the National Radio Astronomy Observatory in Charlottesville, Virginia said in a statement.
"Ideally we should strive to detect other chiral species, especially those of interest in biology or found in meteorites," said NASA Goddard astrophysicist Stefanie Milam, who wasn't involved in the study. "This is a very exciting discovery for astrobiology."
Apart from the staggering existential implications of understanding our own origins, the study of chiral molecules could help scientists figure out how much luck was required for life's intricate double-helix to form. When it comes to the hunt for life on other planets, the question of how special we are is paramount. If the bias of one hand over another is commonplace for chiral molecules, other planets seeded by the same molecular clouds might have a shot at building complex structures like DNA.
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