DNA Replication
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DNA replication produces two new daughter DNA strands that are identical to the original DNA. The resulting DNA strands are semi-conservative, as they contain one strand from the original DNA molecule and one newly synthesized strand.
The process requires DNA helicase to unwind the DNA double helix.
DNA single-stranded binding proteins (SSBPs) bind to single stranded regions of DNA and help stabilize the extended single stranded templates[1].
DNA gyrases catalyses negative supercoils and assist the unwinding process.
Leading strand[edit | edit source]
New DNA strands are intiated by RNA primers, the synthesis of which is catalyzed by enzymes called primases. In the 5’-3’ direction a continuous strand of DNA is created, the leading strand.
Lagging strand[edit | edit source]
Okazaki fragments are created leading to the formation of the lagging strand. Short segments are covalently bound together by polynucleotide ligase.
Y-replication fork[edit | edit source]
DNA replication takes place at multiple points and forms replication forks which, are Y shaped structures. The progresses in both directions forming replication bubbles. The replication origins are approximately 50 to 300 kb (kilobases) apart[2]. After initiation, elongation of the DNA is carried out by DNA polymerase III. Polymerase I subsequently removes RNA primers.
