Question

Competing models for DNA pol 3

The trimeric model has 3 copies of ___, but no ____ of the clamp loader. Both tau and gamma are encoded by the DnaX gene. Gamma is a frameshift of Tau.

Answer 1

The trimeric model of DNA polymerase III contains three copies of the polymerase subunit and no redundancy in the clamp loader, with both tau and gamma subunits arising from the DnaX gene due to a frameshift.

Step-by-step explanation:

The student's question discusses the models for DNA polymerase III, specifically, the trimeric model. In this model, there are three copies of the replicative polymerase subunits, but no redundancy of the clamp loader. Both the tau and gamma subunits are encoded by the DnaX gene. A key distinction to note is that gamma is a truncated form of tau due to a frameshift in the gene, not an alternative gene product.

DNA polymerase III is essential in DNA replication as it synthesizes a new strand that is complementary to the template strand. A frameshift in the DnaX gene results in the production of the shorter gamma subunit from the same gene that produces the tau subunit, which is a remarkable example of the efficiency and versatility of genetic coding.