Which protein prevents the reformation of original base pairs during DNA replication?

During DNA replication, it is crucial to maintain the stability of the unwound single strands of DNA to prevent them from re-annealing or reforming base pairs before they can be replicated. Single-stranded binding proteins play a critical role in this process. After the double helix is unwound by helicase, these proteins bind to the exposed single-stranded regions of DNA. By coating the strands, they stabilize the unwound DNA and prevent the two strands from coming back together, ensuring that the template is accessible for the DNA polymerase to synthesize new complementary strands.

Understanding the roles of other proteins highlights the importance of single-stranded binding proteins. Helicase is responsible for unwinding the double-stranded DNA, while DNA ligase is involved in joining Okazaki fragments on the lagging strand. Gyrase helps relieve the supercoiling tension ahead of the replication fork. However, it is the single-stranded binding proteins that specifically prevent the original base pairs from reforming during the critical replication phase, making it the correct choice in this context.