Protocol Online logo
Top : New Forum Archives (2009-): : Molecular Cloning

Type of polymerases compatible for TA cloning - (Sep/11/2013 )

Good Afternoon All, 

 

I have a minor question about using the TOPO XL vector. I am trying to figure out what type of polymerase would you recommend to use for my PCR due to the 3' deoxythymidine (T) reside overhangs?

 

 

Thank you in advance  

-pmggms2-

Taq polymerase or mixtures of Taq plus a proofreading polymerase will add a 3' A to the product, allowing ligation into the Topo vector. Pure proof reading enzymes such as Phusion, Q5, Pfu will leave blunt end products and will not clone.

-phage434-

In addition, you can add an A overhang after the PCR by adding taq and dATP then incubating for 15 min at 72 C.

-bob1-

Thank you I really appreciate it 

-pmggms2-

So would you recommend hotstar high fidelity polymerase kit to be sufficient? 

 

-pmggms2-

If you are concerned about fidelity (which is perhaps not that important for 1000  bp fragments), then Bob1's answer would be best: do a PCR with a proofreading enzyme, then A tail with Taq and dATP. Otherwise, a Taq/Pfu mixture such as Invitrogen PCR Supermix would be an easy choice of enzyme. I like the master mixes, just because they avoid lots of pipetting and many tubes.

-phage434-

well the gene I am cloning is well over 1kb so I should be worried about fidelity especially since I will be using my product for sequencing 

-pmggms2-

If you are sequencing the PCR product directly, it makes no difference. If you are cloning and then sequencing, then it may be worth it.

-phage434-