Most major biological molecules, including all proteins, DNA and RNA, point in one direction or another. In other words, they are chiral, or handed. Like how your left glove fits only your left hand and your right glove your right hand, chiral molecules can interact only with other molecules of compatible handedness.
  • recklessengagement@lemmy.worldEnglish
    16·
    4 days ago

    Makes me wonder how all life came to use exclusively L-protiens.

    Perhaps there was once a time where they both existed on the primordial earth, and natural selection preferred one over the other.

    • AbouBenAdhem@lemmy.worldEnglish
      10·
      4 days ago

      natural selection preferred one over the other

      Given enough time, a fitness-neutral variant will tend to fixation due to drift alone, unless there are density-dependent effects (i.e., unless being relatively rare increases fitness). The article is concerned that there may be some such effect, but the extinction of any primordial chiral life suggests that there isn’t.

    • MonkderVierte@lemmy.mlEnglish
      3·
      3 days ago

      I read about it a while ago. Apparently, right-chiradial proteins can’t produce some molecules the left ones can or react entirely different. I guess lc was just more practical?

    • catloaf@lemm.eeEnglish
      1·
      4 days ago

      Or one just happened to get access to a resource first (e.g. large clump of nutrients) and just grew faster.