As a researcher who studies cytoskeletal dynamics, you create a microtubule subunit that cannot hydrolyze GTP. How would the critical concentration for the minus end of a polymer formed by these mutant subunits compare to that of the minus end of a fiber formed by normal microtubule subunits? Why? How would the critical concentration for the minus end of a fiber formed by these mutant subunits compare to that of the plus end of a fiber formed by normal microtubule subunits? Why?
As a researcher who studies cytoskeletal dynamics, you create a microtubule subunit that cannot hydrolyze GTP. How would the critical concentration for the minus end of a
Explanation:
The critical concentration for the minus end of a polymer formed by these mutant subunits would be higher than that of the minus end of a fiber formed by normal microtubule subunits. This is because the mutant subunits cannot hydrolyze GTP, so they would not be able to release the subunits at the minus end as easily. This would lead to a higher critical concentration for the minus end.
The critical concentration for the plus end of a fiber formed by these mutant subunits would be lower than that of the plus end of a fiber formed by normal microtubule subunits. This is because the mutant subunits cannot hydrolyze GTP, so they would be more likely to release the subunits at the plus end. This would lead to a lower critical concentration for the plus end.
These results make sense when considering the role of GTP hydrolysis in microtubule dynamics. GTP hydrolysis is thought to be important for microtubule assembly and disassembly, and it has been shown that mutant subunits that cannot hydrolyze GTP have a slower assembly rate and a higher disassembly rate than normal subunits (Desai & Mitchison, 1997). Therefore, it makes sense that the critical concentration for the minus end of a polymer formed by these mutant subunits would be higher since it would take longer for the subunits to be released and that the critical concentration for the plus end of a fiber formed by these mutant subunits would be lower since the subunits would be more likely to be released.
These results also have important implications for the role of GTP hydrolysis in microtubule dynamics. GTP hydrolysis is thought to be important for microtubule assembly and disassembly, and it has been shown that mutant subunits that cannot hydrolyze GTP have a slower assembly rate and a higher disassembly rate than normal subunits (Desai & Mitchison, 1997). Therefore, it is possible that the critical concentration for the minus end of a polymer formed by these mutant subunits is higher because it takes longer for the subunits to be released, and that the critical concentration for the plus end of a fiber formed by these mutant subunits is lower because the subunits are more likely to be released. This could have important implications for the role of GTP hydrolysis in microtubule dynamics.
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