From: invalide@invalid.invalid   
      
   https://scitechdaily.com/calciums-cosmic-secret-how-a-common-min   
   ral-may-have-sparked-life-on-earth/   
      
   Research suggests that calcium may have played   
   a key role in guiding the development of a   
   specific molecular handedness in primitive   
   polyesters and early biomolecules.   
      
   A new study from the Earth-Life Science   
   Institute (ELSI) at the Institute of Science   
   Tokyo has revealed an unexpected role for   
   calcium in the formation of life’s earliest   
   molecular structures. The researchers found   
   that calcium ions can influence the way   
   primitive polymers form, offering new   
   insight into a long-standing mystery: why   
   life’s molecules favor a single type of   
   “handedness,” or chirality.   
      
   Many molecules exist in two mirror-image   
   forms, like left and right hands. However,   
   life on Earth strongly favors one side: the   
   sugars in DNA are right-handed, while   
   proteins are made from left-handed amino   
   acids. This consistent preference, known as   
   homochirality, is critical for life but its   
   origin has remained unclear.   
      
   To explore how early Earth conditions might   
   have shaped this molecular preference, the   
   team studied tartaric acid (TA), a simple   
   molecule with two chiral centers. They found   
   that calcium has a major effect on how TA   
   molecules join to form polyesters. In the   
   absence of calcium, pure left- or   
   right-handed TA forms polymers easily, while   
   mixtures of both forms do not. When calcium   
   is present, this behavior   
   flips—polymerization of pure TA slows down,   
   but mixed solutions begin to form polymers.   
      
   “This suggests that calcium availability   
   could have created environments on early   
   Earth where homochiral polymers were favored   
   or disfavoured,” says Chen Chen, Special   
   Postdoctoral Researcher at RIKEN Center for   
   Sustainable Resource Science (CSRS), who   
   co-led the study.   
      
   ...   
   What makes this study especially intriguing   
   is its suggestion that polyesters—simple   
   polymers formed from molecules like tartaric   
   acid—could have been among life’s earliest   
   homochiral molecules, even before RNA, DNA,   
   or proteins. “The origin of life is often   
   discussed in terms of biomolecules like   
   nucleic acids and amino acids,” ELSI’s   
   Specially Appointed Associate Professor   
   Tony Z. Jia, who co-led the study, explains.   
   “However, our work introduces an alternative   
   perspective: that ‘non-biomolecules’ like   
   polyesters may have played a critical role   
   in the earliest steps toward life.”   
      
   Calcium-poor settings, such as some lakes or   
   ponds, may have promoted homochiral polymers,   
   while calcium-rich environments might have   
   favored mixed-chirality polymers.   
      
   --- SoupGate-DOS v1.05   
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