List the order in which the following proteins and enzymes are active in E. coli DNA replication: DNA pol I, SSB, ligase, helicase, DNA pol III, and primase.

Key Concepts

DNA Replication Process

DNA replication in E. coli is a highly coordinated process involving multiple proteins and enzymes that work sequentially to ensure accurate duplication of the genetic material. The process begins at the origin of replication and proceeds in a specific order to synthesize new DNA strands, utilizing both leading and lagging strand mechanisms.

Role of Key Enzymes

Each enzyme involved in DNA replication has a distinct role. For instance, helicase unwinds the DNA double helix, single-strand binding proteins (SSB) stabilize the unwound strands, primase synthesizes RNA primers, DNA polymerase III extends the DNA strand, DNA polymerase I replaces RNA primers with DNA, and ligase seals the gaps between Okazaki fragments on the lagging strand.

Sequential Activity of Enzymes

The activity of these enzymes follows a specific sequence to ensure efficient replication. First, helicase unwinds the DNA, followed by SSB binding to stabilize the strands. Primase then lays down RNA primers, allowing DNA pol III to synthesize the new DNA. Afterward, DNA pol I removes the primers and fills in the gaps, and finally, ligase connects the fragments, completing the replication process.