Polymerases

Further, by understanding the detailed mechanisms of human Pol II, researchers can now explore the development of molecules that could inhibit viral and bacterial polymerases while reducing harmful interactions with human polymerases.

All know viral DNA polymerases belong to the DNA pol families A and B. All possess a 3'-5'- exonuclease domain with three sequence motifs Exo I, Exo II and Exo III.

Because DNA replication does not begin at either end of the DNA strand, but starts in the center, and considering that all known DNA polymerases move in the 5' to 3' direction, one finds a leading and a lagging strand on the DNA molecule being replicated.

Because it is tightly packed, it was thought to be inaccessible to polymerases and therefore not transcribed, however according to Volpe et al.

Hot-start/cold-finish PCR is achieved with new hybrid polymerases that are inactive at ambient temperature and are instantly activated at elongation temperature.

In DNA replication, DNA-dependent DNA polymerases make copies of DNA polynucleotide chains.

In eukaryotic replication, the primase forms a complex with Pol α. citation Multiple DNA polymerases take on different roles in the DNA replication process.

It is worth noting that primers are not always for DNA synthesis, but can in fact be used by viral polymerases, e.g. influenza, for RNA synthesis.

Many DNA polymerases have a proofreading activity.

Monoubiquitinated PCNA recruits polymerases that can carry out DNA synthesis with damaged DNA; but this is very error-prone, possibly resulting in the synthesis of mutated DNA.

Niacinamide also inhibits poly(ADP-ribose) polymerases (PARP-1), enzymes involved in the rejoining of DNA strand breaks induced by radiation or chemotherapy.

Polymerases are classified according to the type of template that they use.

Some of these enzymes are used in molecular biology (for example, heat-stable DNA polymerases for PCR ), and in washing agents.

The DNA polymerases initially employed for in vitro experiments presaging PCR were unable to withstand these high temperatures.

The polymerases from the archaea are similar to family B DNA Pols.

There are also a number of RNA-dependent RNA polymerases that use RNA as their template for synthesis of a new strand of RNA.

These proposals were based on an analysis of the RNA polymerases and are still under consideration.