[HN Gopher] Discovery of ultrafast myosin, its amino acid sequen...
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       Discovery of ultrafast myosin, its amino acid sequence, and
       structural features
        
       Author : bryanrasmussen
       Score  : 31 points
       Date   : 2022-02-27 17:00 UTC (6 hours ago)
        
 (HTM) web link (www.pnas.org)
 (TXT) w3m dump (www.pnas.org)
        
       | lysozyme wrote:
       | Myosin is a very cool protein because it's a physical and direct
       | link between the microscopic world of atoms and electrical
       | charges and the macroscopic world of moving bodies.
       | 
       | How myosin and other protein machines work at the atomic level is
       | actually pretty well-known! [1] Myosin and its partner actin use
       | the same biophysical principles, such as hydrogen binding and
       | protein conformational change, as other proteins. But whereas
       | other proteins typically act on the scale of atoms (doing things
       | we think of as "chemistry", such as making or breaking chemical
       | bonds), myosins and other molecular machines are directly and
       | physically responsible for the macro-scale movements of beating
       | wings, walking legs, and beating hearts.
       | 
       | On the subject of molecular machines: it's sometimes asked why
       | biology doesn't use the wheel. Protein machines like ATP synthase
       | [2] (which creates the ATP used by myosin to create movement)
       | provide an answer
       | 
       | 1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6618170/
       | 
       | 2. https://pubmed.ncbi.nlm.nih.gov/7704582/
        
         | dopylitty wrote:
         | Motor proteins are so incredibly cool. Like many others I was
         | blown away by the 3D animated Inner Life of the Cell[1] showing
         | these proteins physically walking around in the cell.
         | Previously I had this idea that cells were just blobs of jelly
         | and somehow they interacted with each-other to produce macro
         | phenomena like muscle movement.
         | 
         | And then you get into the other protein machines like the ATP
         | synthase in the mitochondria [2] (also linked below) which are
         | actually little motors/pumps. And we all have billions of these
         | inside use spinning away. It's just amazing.
         | 
         | 1. https://youtu.be/wJyUtbn0O5Y?t=80 2.
         | https://www.youtube.com/watch?v=kXpzp4RDGJI
        
           | mncharity wrote:
           | > the 3D animated Inner Life of the Cell[1] showing these
           | proteins physically walking
           | 
           | Reality is even more interesting. The animation regrettably
           | prioritizes "art" over accuracy and education/misconceptions.
           | Between one "step" and the next, the kinesin "legs" are
           | violently flailing around, and the payload has time to
           | explore the entire configuration space reachable given the
           | tether. Think not of a donkey towing a barge, but of a mouse,
           | its tail tied to a balloon, clinging to a wire, in a
           | hurricane! The nanoscale atomic mosh pit from hell. And IIRC,
           | the "steps" are often backward - forward is merely net more
           | frequent. "Art"... basically "video frames" have been highly
           | selected to tell a bogus narrative, without even a brief hint
           | of a reality check. It's like editing a video of some
           | politician jogging to show unmoving legs and divine
           | levitation. Nanoscale reality is much more fun.
        
         | whoisburbansky wrote:
         | Professor Lue from Harvard has a pretty cool visualization of
         | how ATP synthase uses rotation and the energy produced through
         | cellular respiration to produce ATP at
         | https://www.youtube.com/watch?v=kXpzp4RDGJI, slightly more
         | visceral than digging through a paper for a layperson.
        
           | lysozyme wrote:
           | Thank you for posting this link. The video does a very good
           | job of connecting the molecular details (even down to the
           | geometry of a transition state structure) to the macro-scale
           | movements of ATP synthase
        
         | dekhn wrote:
         | Throughout my biophysics phd motor proteins were a big topic in
         | adjacent labs. Myosin was originally the one everybody was
         | going to focus on, but the structural biophysics were
         | challenging (for a long time the only model was a C-alpha
         | structure in the PDB). Many people switch to kinesin, which
         | seems to be easier to study (other grad students built their
         | own microscopes that could track single molecules of
         | fluorescently labelled kinesin moving around on a tiny slide).
         | Last I had checked most of them were pretty confident the basic
         | principles of kinesin had been worked out, but I dont think
         | that means we can do any sort of arbitrary molecular
         | engineering using kinesin as a motor.
        
       | politician wrote:
       | What are myosins?
       | 
       | " Myosins are motor proteins that convert chemical energy, ATP,
       | to physical force to move actin filaments. Phylogenetic analyses
       | of myosin motor domain (MD) sequences have shown that there are
       | at least 79 myosin classes, with several subclasses under each
       | class."
        
         | bryanrasmussen wrote:
         | https://en.wikipedia.org/wiki/Myosin
        
       | kavalg wrote:
       | What could be the possible applications of this?
        
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       (page generated 2022-02-27 23:01 UTC)