The KlenTaq mystery

Ted Michelini tedm at
Sun Mar 17 00:49:57 EST 1996

Another relevant point may be that Wayne Barnes invented KlenTaq. 
I am confused as to the mention of longrange PCR conditions (exo minus 
Pol/trace exo plus Pol) and TA cloning. I use Vent only to blunt my PCR 
products and if it chews off the 3' A or fills in the 5' missing T your 
efforts to TA clone will be greatly complicated. I have thought that the 
long PCR enzyme mix was anethema to TA cloning, tell me if I'm mistaken. 	
Perhaps you are A tailing after your long PCR, if so ignore this... 
	I'd thought that any advatage that Stoffel or Klentaq had was in some 
sort of primer extension reaction where the 5-3 exo would mess things 
up, it is somewhat more thermostable as well. A good comparison of Taq 
and Stoffel comes in the Roche Molecular Systems Taq expression 
/purification paper, and this may answer some of your questions. I'm not 
sure I put much weight in the claimed increase in fidelity for Klentaq, 
as this is highly dependant on the assay (as well as being quite small)
Perhaps patents are more tenable with "engineered"(read truncated) forms 
of a naturally occuring protein, eh?

Ted Michelini
Institute of Molecular Biology
University of Oregon

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