Muscle contraction question about myosin

  • Thread starter kolleamm
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  • #1
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I've been doing research on how muscles work using the page below and overall I get the general idea, however I still have some questions.
Why does ADP and Pi detach from the myosin head during the power stroke and why does the attachment of ATP to the myosin head cause the myosin head to detach from actin?

https://courses.lumenlearning.com/wm-biology2/chapter/atp-and-muscle-contraction/

Thanks!
 

Answers and Replies

  • #2
326
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I've been doing research on how muscles work using the page below and overall I get the general idea, however I still have some questions.
Why does ADP and Pi detach from the myosin head during the power stroke and why does the attachment of ATP to the myosin head cause the myosin head to detach from actin?

https://courses.lumenlearning.com/wm-biology2/chapter/atp-and-muscle-contraction/

Thanks!

Proteins in general have a behavior called allostery. A ligand binds to the protein and changes the protein's binding affinity for another ligand at a different binding site of the protein. Allostery is mediated by networks of intra-molecular hydrogen bonds between allostery participating amino acid residues as described in a paper.

At a molecular biology level, you can usually explain this kind of thing using conformational changes.
Without looking into research articles, my hypothesis is that detachment of the ADP and Pi causes the myosin to change its conformation, and this conformation change is associated with the power stroke. Attachment of ATP to the myosin head causes the myosin to change conformation and lowers its binding affinity to actin.
 
  • #3
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Allostery is mediated by networks of intra-molecular hydrogen bonds between allostery participating amino acid residues as described in a paper.
Thanks for your response. So basically a complex network of molecules controls the attachment and detachment preference on myosin?
 
  • #4
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Thanks for your response. So basically a complex network of molecules hydrogen bonding networks control the attachment and detachment preference on myosin?

Yes. If you bind a ligand to a protein it slightly changes the shape of the entire protein, including the shape of other ligand binding site. the whole thing about allostery can be explained using different concepts like entropy transfer, thermodynamics, energetics, or energy conservation but they all describe the same thing.
 
  • #5
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Yes. If you bind a ligand to a protein it slightly changes the shape of the entire protein, including the shape of other ligand binding site. the whole thing about allostery can be explained using different concepts like entropy transfer, thermodynamics, energetics, or energy conservation but they all describe the same thing.
Thanks for the explanation it really helped.
 

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