animation of DNA replication

The chain elongation reaction catalyzed by DNA polymerases is a nucleophilic attack by the 3’-OH group of the primer on the innermost phosphorus atom of the deoxynucleoside triphosphate. A phosphodiester bridge forms with the concomitant release of pyrophosphate. The subsequent release of pyrophosphate by pyrophosphatase helps drive the polymerization forward.

***Elongation of DNA chain proceeds 5’-to-3’ direction.
***Template directed enzyme also have nuclease activity.

Maurice Wilkins-Rosalind Franklin (x-ray diffraction photos of fibers of DNA)
Erwin Chargaff (nucleotide ratios in DNA)
Watson-Crick (DNA structure)
Matthew Meselson-Franklin Stahl ( semiconservative replication)

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