Which protein prevents unzipped DNA strands from reattaching during replication?

During DNA replication, the two strands of the double helix must be separated to allow the synthesis of new strands. Once these strands are unzipped, they become vulnerable to re-annealing or reattaching to each other. The role of single-strand binding protein (SSB) is crucial in this process.

Single-strand binding proteins attach to the exposed single strands of DNA during replication and stabilize them, preventing them from reforming the double helix. This ensures that the replication machinery can access and synthesize the new complementary strands without interruption or errors.

In contrast, helicase is responsible for unwinding the DNA double helix, ligase is involved in joining Okazaki fragments on the lagging strand during replication, and topoisomerase alleviates the tension that arises ahead of the replication fork by making cuts in the DNA to prevent supercoiling. These proteins have different roles in the replication process, highlighting the specialized function of single-strand binding proteins in maintaining the integrity of the separated DNA strands.