Question

What would be the impact of the loss of processivity on DNA Pol III?

Short answer

Answer: Reduced processivity in DNA Pol III may lead to decreased replication speed, increased error rates during replication, processing issues with Okazaki fragments, and potential compensation from other replication enzymes. Ultimately, these consequences may impact cellular viability, leading to slower replication, increased mutation rates, and potential genomic instability.

Step-by-step solution

Impact on replication speed

DNA Pol III with reduced processivity will dissociate from the template DNA more frequently during replication. This will significantly hinder replication progress since the enzyme will need to reattach multiple times, decreasing replication speed and elongation efficiency.

Impact on replication fidelity

Processivity is important for ensuring replication fidelity. DNA Pol III's increased dissociation rates due to lower processivity might lead to a higher error rate or more frequent stalling, as DNA Pol III might not be able to efficiently correct mismatched base pairs before detaching from the DNA.

Impact on Okazaki fragment processing

Loss of processivity in DNA Pol III may affect the processing of Okazaki fragments during lagging strand synthesis. Frequent dissociation of the enzyme may cause an increase in the number of Okazaki fragments, potentially affecting overall replication efficiency.

Compensation by other replication enzymes

Other replication enzymes, such as DNA Pol I or the sliding clamp (β clamp), may be able to partially compensate for the loss of processivity in DNA Pol III. However, this may not fully restore replication efficiency, and it might increase the chances of errors in DNA synthesis.

Overall impact on cellular processes

DNA replication is a fundamental process in cell division and growth. A significant reduction in processivity of DNA Pol III may have broad implications for cellular viability. It may lead to slower replication, increased mutation rates, and potential genomic instability, ultimately affecting normal cell function and potentially leading to a higher chance of disease or dysfunction.