Muscle contraction question about myosin

In summary, allostery is a behavior exhibited by proteins where a ligand binding to one part of the protein can change its binding affinity for another ligand at a different site. This is mediated by networks of intra-molecular hydrogen bonds between specific amino acid residues. In the context of muscle contraction, the detachment of ADP and Pi from the myosin head causes a conformational change that leads to the power stroke. Similarly, the attachment of ATP to the myosin head causes another conformational change that lowers its binding affinity for actin. This process is controlled by a complex network of molecules and can be explained using different concepts such as entropy transfer, thermodynamics, energetics, and energy conservation. Overall,
  • #1
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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  • #2
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.
 
  • #3
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?
 
  • #4
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.
 
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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.
 

1. What is myosin?

Myosin is a protein found in muscle cells that plays a crucial role in muscle contraction. It is a motor protein that uses energy from ATP to generate force and movement.

2. How does myosin contribute to muscle contraction?

Myosin binds to actin, another protein in muscle cells, and forms cross-bridges. When ATP is hydrolyzed, the myosin head changes shape and pulls on the actin, causing muscle contraction.

3. What is the structure of myosin?

Myosin has a long tail and a globular head region. The tail attaches to other myosin molecules to form thick filaments, while the heads extend outwards to interact with actin.

4. How does myosin interact with other proteins during muscle contraction?

Myosin interacts with actin, tropomyosin, and troponin to regulate muscle contraction. When calcium ions are released, they bind to troponin, causing a conformational change that moves tropomyosin out of the way and exposes the binding sites on actin for myosin to attach.

5. Are there different types of myosin?

Yes, there are multiple types of myosin found in different types of muscle cells. For example, skeletal muscle has myosin II, while smooth muscle has myosin I and V. Each type of myosin has unique properties and functions in muscle contraction.

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