List and describe the function of the ten subunits constituting DNA polymerase III. Distinguish between the holoenzyme and the core enzyme.

Answer: The holoenzyme of DNA polymerase III is the complete and fully functional form, consisting of all ten subunits. It is capable of efficiently performing all activities related to DNA replication, such as polymerization, proofreading, clamp loading, and processivity. In contrast, the core enzyme consists of only three subunits (Alpha, Epsilon, and Theta) and possesses polymerization and proofreading activities but lacks the high processivity and clamp loading activity found in the holoenzyme. The functions of the ten subunits of DNA polymerase III are as follows: 1. Alpha (α): main component responsible for polymerization activity. 2. Epsilon (ε): proofreading exonuclease to maintain replication fidelity. 3. Theta (θ): stimulates the proofreading activity of the epsilon subunit. 4. Tau (τ): coordinates the activities of two polymerases on both strands during replication. 5. Gamma (γ): performs a similar function to tau and can substitute it. 6. Delta (δ): involved in DNA clamp loading for the Beta subunit. 7. Delta Prime (δ'): functions together with the delta subunit in clamp loading. 8. Chi (χ): enhances processivity by binding to single-stranded DNA binding proteins. 9. Psi (ψ): stabilizes the interaction between the Tau subunit and other holoenzyme subunits. 10. Beta (β): forms a sliding clamp around the DNA for processive replication.