Muscle contraction question about myosin

AI Thread Summary
The discussion focuses on the mechanics of muscle contraction, specifically the roles of ADP, Pi, and ATP in the myosin head's attachment and detachment from actin. It highlights that the detachment of ADP and Pi during the power stroke leads to a conformational change in myosin, facilitating muscle contraction. The attachment of ATP to myosin causes another conformational change, reducing its affinity for actin and prompting detachment. The conversation also touches on the concept of allostery, where ligand binding alters the protein's shape and function through networks of hydrogen bonds. Overall, a complex interplay of molecular changes governs muscle contraction dynamics.
kolleamm
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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!
 
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kolleamm said:
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.
 
docnet said:
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?
 
kolleamm said:
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.
 
docnet said:
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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