Which one of the following statements about clamp loader is NOT correct?​

Correct option is C

The correct answer is: (3) In the absence of ATP, clamp loader attains a spiral shape to bind and open the clamp.

Explanation:
In the absence of ATP, the clamp loader does not attain a spiral shape. In fact, the clamp loader operates in an ATP-dependent manner. The clamp loader, which is a five-subunit complex, binds to the sliding clamp (such as the PCNA clamp in eukaryotes or the clamp loader complex in prokaryotes) in an ATP-bound state, and this binding induces a conformational change that allows the clamp to open. Once ATP is hydrolyzed, the clamp loader releases the clamp and the DNA polymerase is able to use the clamp for DNA synthesis.

Information Booster:

1. The clamp loader is a five-subunit complex (heteropentamer) that facilitates the loading of the sliding clamp onto the DNA. This is essential for the efficient functioning of DNA polymerase during replication.

2. Clamp loading is ATP-dependent, as the process involves the hydrolysis of ATP, which provides the energy needed to open and close the sliding clamp around the DNA strand.

3. The spiral shape of the clamp loader is actually induced by ATP binding, not in the absence of ATP. ATP binding triggers the conformational change required for the clamp loader to interact with the sliding clamp.

4. The C-terminal face of the sliding clamp is a crucial docking site where both the clamp loader and DNA polymerase interact, and they do compete for this region for proper assembly and function during DNA replication.

Additional Knowledge:

• The clamp loader is a five-subunit heteropentamer (option 1) is correct. It consists of five subunits that work together to load the sliding clamp onto the DNA.

• Clamp loading is an ATP-dependent process (option 2) is correct. ATP hydrolysis is necessary for the clamp loader to open the sliding clamp and load it onto the DNA.

• The clamp loader and DNA polymerase compete for the same C-terminal face of the clamp (option 4) is correct. Both the clamp loader and DNA polymerase interact with the same part of the sliding clamp during DNA replication.