Polymerase


A polymerase is an enzyme that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by copying a DNA template strand using base-pairing interactions or RNA by half ladder replication.
A DNA polymerase from the thermophilic bacterium, Thermus aquaticus is used in the polymerase chain reaction, an important technique of molecular biology.
A polymerase may be template dependent or template independent. Poly-A-polymerase is an example of template independent polymerase. Terminal deoxynucleotidyl transferase also known to have template independent and template dependent activities.

Types

In general, viral single-subunit RNA polymerases/replicases/reverse transcriptase shares a common origin with DNA polymerase. They have a conserved "palm" domain. Multi-subunit RNA polymerase forms an unrelated group. Primases have a more complex story: bacterial primases with the Toprim domain are related to topoisomerase and mitochrondrial helicase, while archaea and eukaryotic primases form an unrelated family, possibly related to the polymerase palm. Both families nevertheless associate to the same bunch of helicases.

See Also