Specific sequence on the DNA molecule (~250 bases).
Recognized by initiation proteins.
Key Proteins Involved:
DNA A:
First protein to bind to the REC.
Initiates the separation of DNA strands.
DNA B Helicase:
ATP-dependent enzyme for unwinding the DNA helix.
Facilitated by DNA-C loader protein.
Two DNA-B molecules are loaded, one onto each DNA strand.
This setup can also be referred to as the "prime ozone."
Mechanism of Helicase Activity
Function of DNA B Helicase:
Uses ATP to spin and break hydrogen bonds between nucleotides.
Creates a replication fork as it moves along the DNA.
Single-Stranded Binding Proteins:
Bind to the lagging strand.
Prevent reformation of hydrogen bonds between complementary bases.
Role of Topoisomerase
DNA Gyrase (Topoisomerase 2):
Breaks the DNA molecule ahead of the replication fork.
Relieves tension generated by the unwinding of the DNA helix.
Summary
The process of DNA replication in prokaryotes involves multiple proteins and enzymes that work together to ensure efficient and accurate DNA synthesis. This process is crucial for cell division and is tightly regulated by the interaction of various molecular components.