Methyl-accepting chemotaxis proteins (MCPs) are a class of transmembrane receptors in bacteria like E. coli that play a crucial role in chemotaxis - the movement of an organism in response to chemical stimuli.

1. Detection of Attractant Gradient: When an attractant gradient is detected, the attractant molecules bind to the MCPs on the surface of the E. coli cell.

2. Conformational Change: This binding causes a conformational change in the MCPs, which is essentially a change in the shape of the protein.

3. Signal Transduction: This conformational change triggers a signal transduction pathway inside the cell. The MCPs interact with other proteins in the cell, including a protein called CheA.

4. CheA Phosphorylation: The interaction with the MCP causes CheA to become phosphorylated, meaning a phosphate group is added to the protein.

5. CheY Phosphorylation: The phosphate group is then transferred from CheA to another protein called CheY.

6. Flagellar Rotation: Phosphorylated CheY interacts with the flagellar motor, causing it to rotate in a certain direction.

7. Cell Movement: This rotation propels the E. coli cell towards the attractant.

8. Adaptation: Meanwhile, the MCPs are adapted by the addition of methyl groups, a process called methylation. This reduces their sensitivity to the attractant, allowing the cell to adapt to the new level of attractant and continue to respond to changes in the attractant concentration.

So, in response to an attractant gradient, E. coli moves towards the attractant by changing the rotation of its flagella, a process controlled by the MCPs and the proteins they interact with.

Question

Methyl-accepting chemotaxis proteins (MCPs) are a class of transmembrane receptors in bacteria like E. coli that play a crucial role in chemotaxis - the movement of an organism in response to chemical stimuli.

1. Detection of Attractant Gradient: When an attractant gradient is detected, the attractant molecules bind to the MCPs on the surface of the E. coli cell.

2. Conformational Change: This binding causes a conformational change in the MCPs, which is essentially a change in the shape of the protein.

3. Signal Transduction: This conformational change triggers a signal transduction pathway inside the cell. The MCPs interact with other proteins in the cell, including a protein called CheA.

4. CheA Phosphorylation: The interaction with the MCP causes CheA to become phosphorylated, meaning a phosphate group is added to the protein.

5. CheY Phosphorylation: The phosphate group is then transferred from CheA to another protein called CheY.

6. Flagellar Rotation: Phosphorylated CheY interacts with the flagellar motor, causing it to rotate in a certain direction.

7. Cell Movement: This rotation propels the E. coli cell towards the attractant.

8. Adaptation: Meanwhile, the MCPs are adapted by the addition of methyl groups, a process called methylation. This reduces their sensitivity to the attractant, allowing the cell to adapt to the new level of attractant and continue to respond to changes in the attractant concentration.

So, in response to an attractant gradient, E. coli moves towards the attractant by changing the rotation of its flagella, a process controlled by the MCPs and the proteins they interact with.

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