I wonder that , does the DNA polymerase deattach from the DNA double helix after the sequens between two primer is complated?
What I am trying to ask is that, If I have a 200 nt single strand DNA, and one forward primer only. Does the DNA polymerase will be deattached from the DNA after the 2nd strand is finished.
______________________ First strand
--- Primer
_____________________ Double Helix is complated by polymerase
_____________________
now is the DNA polymerase attached near the 3 prime of the new strand or it will be deattach and search for new primer to extend? Is DNA denaturatin a must for polymerase-DNA deattachment?
Thanks for answers.
It depends on the processivity of the polymerase you are using. Processivity is the number of nucleotides added by a polymerase before detaching from the template DNA. It can remain attach to the template if it processivity is high and template is long. Or if the processivity is low it will detach even before strand synthesis is complete (and taken up by other polymerase molecule present in the reaction mixture). For example for longer templates, a template holding domain is fused with the polymerase to increase its processivity.
Taq polymerase adds approx 50 nt per binding event.
After strand synthesis it surely is detached.
https://www.neb.com/tools-and-resources/feature-articles/anatomy-of-a-polymerase-how-structure-effects-function
I have high fidelity DNA polymerase, and normally it can complate the synthesis of more than 1kb I was asking that if the extentioned sequence is like 200 nt that processivity created no problem, Does the DNA polymerase keeep attaching 3' and or when theere is no more order to extend it will deattach by itself?
As I understand from your answer, it will deattach without denaturating of DNA by itself when the double helix is complated.
Thanks for your answer.
http://scienceprimer.com/dna-polymerase
https://www.ncbi.nlm.nih.gov/books/NBK22374/
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