Question

why is it important to know that the primase function 1000 time when associated with helicase

Answer 1

Question:

Why it is important to know that the primase function 1000 time when associated with helicase.

Answer:

During DNA replication, for the leading strand a special primer is needed only at the stat of replication. On the lagging side of the fork, a special RNA primer is synthesized by an enzyme DNA Primase which uses ribonucleoside triphosphates. For the DNA replication to proceed, the double helix must be opened up ahead of the replication fork, so that the incoming deoxyribonucleotide triphosphates can form base pairs with the temple strand. Two types of proteins contribute to this process - DNA helicases and single stranded DNA binding proteins.

DNA helicase consist of six identical subunits bind with ATP molecules. The hydrolysis of ATP change the shape of the protein molecule in a cylindrical manner that allows the protein to propel themselves rapidly along a DNA strand. When the enzyme encounter a region of DNA double helix it continue to move along the strand, thereby prying the helix at rates upto 1000 nucleosides per second.

Primase is activated by helicases. Primase and Helicase affect each others activity by modulating initiation specificity, stimulating primer synthesis, reducing the length of primers synthesized and increasing its affinity for the single stranded DNA. ATPase and helicase activity of helicase is stimulated by primase due to the stabilization of helicase hexamer by the interaction of helicases with Primase. It resulted in the increased ATP hydrolysis DNA binding and unwinding.